Sutton's Locomotive Workshop British Railways Sulzer Type 2 User manual
OPERATING MANUAL
D5000-D5113(later 24001-24113)
BRITISH RAILWAYS SULZER TYPE 2
4mm : 1ft (1:76.2) scale working model
OPERATING MANUAL
For the Sutton’s Locomotive Workshop
4mm:1ft scale working model of the
British Railways/Sulzer Type 2 locomotive
Chapter Contents Page
1 Preface 5
2 Prototype overview (from 1958) 9
Mechanical Design; Principal Data; Locomotive Structure;
Bogie; Cab Equipment; Engine and Accessories;
Generator and Auxiliaries; Traction Motors; Control Equipment;
Control Scheme; Protective Devices; Brakes; Steam Generator.
3 Spotting features 21
4 Model description 24
5 Display and set-up 25
6 Additional detailing parts 26
7 Running-in and maintenance 28
8 Lighting and printed circuit board 29
9 Wheels and bogies 31
10 Digital sound operation 32
Introduction; Specification; How a real locomotive works;
Prototypical brake application; Special control features;
Global commands; Practical applications;
Useful suggestions; Analogue sound operation.
11 Function button list 46
12 Troubleshooting guide 48
13 Spare parts and enhancements 50
14 Warranty and statutory information 51
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Special acknowledgement must go to my Personal Assistant and RAIL EXCLUSIVE’s
General Manager, Jamie Walsh, without which this project would have never come to
fruition. An able research assistant, she has provided valuable input, enthusiasm, and
much-needed cajoling whilst maintaining an ecient and smooth-running front oce.
ere are several others to thank for their assistance (you know who you are), having
provided invaluable advice, background information, and access, in most cases
completely unknowingly! is model is dedicated to ‘Hawker’, the oce cat, who was
ever-present during the design phase, providing welcome company during long winter
nights in front of the computer screen, especially when it became hard going.
1. Preface
THE IMPETUS behind the launch of Sutton’s Locomotive Workshop (SLW)
is a long-running frustration with existing model railway products. is
project was initiated at a time when, in contradiction to the upward trajectory
of other hobbies, models of my interest period were actually in decline – in
quality, in detail, and in accuracy. With 30 years of railway modelling and
journalism under my belt, I have seen plenty of lame reasons oered for this
inexcusable situation. Having commissioned items from every mainstream
manufacturer in recent years, the general disinterest in product development
and detail enhancements has been readily apparent, with the frequent
response to requests of ‘Sorry, but that’s just not possible’.
For too long, enthusiasts of the diesel era have been pushed to the bottom
of the pile. My heavily critical, pro-diesel stance at manufacturers’ trade
presentations quickly marked me out as a source of irritation. at labelling
made me think. Next came a deliberate policy of dumbing-down models with
its attached ‘design clever’ tag line. en the revelation came that the tting of
detail such as sprung buers was regarded as being prohibitively expensive. All
this was regurgitated as fact by the model railway media without question.
Was I the only one who translated what I saw as ‘marketing spin’ covering an
excuse to charge higher prices for less detail? at really did make me think
again. e nal straw came with a dispute over a crucial commission and the
total disregard for accuracy and timescale by the contracted manufacturer.
ere must be a better way. Better design. Better delity. Better crasman-
ship. Better quality. Why not produce a premium model by pushing tried
and tested engineering principles to their limits and then introduce some
simple, long-wanted, innovations? By virtue of getting the basic shape
correct and making a ‘proper job of it’ the result should be a denitive,
value-for-money product that is eectively future-proofed. So, as the saying
goes: If you want something doing properly, then do it yourself. is is
exactly what the SLW team has done. Meticulously researched using only
primary sources anddesigned in England (by an enthusiast,notby committee),
we then searched worldwide and recruited the very best engineers and
toolmakers who, along with our skilled factory technicians, have brought this
model to fruition.
But enough of what some may interpret as a crusade. is model has, quite
simply, been made to museum-quality standard (and our engineers say an
obsessive level of detail) in order to satisfy the demands of the intelligent
RAIL EXCLUSIVE
Finescale Model Collection
SLW Class 24 Operating Manual Page 5
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modeller/collector and oen forgotten early diesel acionado. We have
worked to a specication, not to a price, and have endeavoured to reduce the
areas of compromise to a minimum. Yes, manufacturing costs have risen, but
not to the degree that the big manufacturers would have you believe. It’s the
prot expectation that causes the real pain your the pocket. By accepting a
much smaller margin (SLW has lower costs, no shareholders, no middlemen
and no big premises) and paying the going rate for what is an incredibly high
element of hand assembly, we have been amazed at what can be achieved by
investing in a world-class manufacturing set-up.
With a love of the mundane, the BR/Sulzer ‘Derby’ Type 2 was an obvious
starting point. One of those ‘bread and butter’ designs that led the way as
part of the well-documented Pilot Scheme it continued in production for a
decade resulting in a build total of 478 machines with an incredibly diverse
geographical spread. ‘Ugly ducklings’ they may have been (outside design
consultants said they wouldn’t even attempt to make a silk purse out of this
pig’s ear) but they heralded the dicult transition from steam to diesel.
Enjoy this model, released shortly aer the 175th anniversary of the rail
industry in Derby, where the rst locomotive of this type was designed and
built. Our rst model also serves to mark the important role these particular
machines, and the men that built and operated them, played in the
modernisation of Britain’s railway.
Apart from an ocial contemporary report on the rst locomotive, we
have refrained from providing a comprehensive history of the type. Such
background articles have been relatively commonplace and we leave the
excitement of research to the customer. A word of caution is, however, advised
with many newer books and magazines perpetuating inaccurate information.
A useful start can be made with Sulzer Diesel Locomotives of British Rail
by Brian Webb, David & Charles, 1978 and Sulzer Types 2 & 3 by ATH Tayler,
Ian Allan, 1984. A visit to David Hill’s superb Derby Sulzers website at
www.derbysulzers.com is also highly recommended.
Please support this bold venture into R-T-R model manufacturing, with its
radically dierent philosophy that ies in the face of current trends. We need
the support of every one of you to thrive in a crowded market dominated by
large multi-national and foreign concerns. Making a success of these rst few
releases will ensure we can tackle even more projects. Please do not hesitate
(in fact we positively encourage you) to contact us with sensible suggestions
for future model variations and areas for improvement.
Philip Sutton King’s Clie, East Northamptonshire. December 2015.
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2. Prototype overview
By way of nostalgic introduction to the prototype, no description could be better
provided than by reproducing the ocial trade press handout that accompanied the
ocial unveiling of the rst locomotive - No. D5000 - in 1958 for formal inspection by
General Sir Brian Robertson, Chairman of the British Transport Commission.
BRITISH RAILWAYS
TYPE 2 1,160h.p.
DIESEL-ELECTRIC LOCOMOTIVE
On view at
MARYLEBONE STATION
24th July 1958
By courtesy of the British Transport Commission
e locomotive which is exhibited at Marylebone Station today is the rst of a batch
of 30 which are being built at British Railways’ Derby Locomotive Works. e total
number of locomotives to be erected by British Railways workshops, incorporating
B.T.H. electrical apparatus and Sulzer 6LDA28 engines, is now 114*.
* e ‘pilot scheme’ build was for 20 locomotives placed in 1955. In June 1957, a further 10
locomotives were ordered for the Eastern Region. Just a month before this presentation, in June
1958, an additional 84 machines were authorised (66 for ER and 16 for the NER). So much for
the plan to gain in-service experience before placing big orders!
At the beginning, the rst 15 of these 30 locomotives will be allocated to the
Southern Region. ere they will be used to implement this Region’s policy whereby
steam traction will be eliminated as soon as possible from their Eastern and Central
Sections. Aerwards, when the 1,550hp locomotives on order with the Birmingham
Railway Carriage & Wagon Co., also with Sulzer diesel engines, arrive, these 15 built
at Derby will be re-allocated.
Mechanical Design
ese locomotives, Nos. D5000 – D5029, are being designed and constructed to the
requirements of the British Transport Commission under the general direction of
Messrs. R. C. Bond and S. B. Warder (Chief Mechanical Engineer and Chief Electrical
Engineer respectively, of the British Railways Central Sta, British Transport
Commission), the detailed design and supervision of construction being the
responsibility of Mr. J. F. Harrison (Chief Mechanical and Electrical Engineer, Derby,
London Midland Region). e whole design has been co-ordinated with
the British omson-Houston Co. who are the main contractor for the power
equipment, and with Sulzer Brothers, the diesel engine manufacturers.
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e locomotives are of the Bo-Bo type having a designed weight in working order
of 75 tons. Each locomotive is of the full width body type with a driving cab at each
end. It has multiple unit equipment enabling it to operate in multiple, not only with
locomotives of the same design but with all locomotives for the British Railways
modernisation scheme equipped with BTH, Crompton-Parkinson or English Electric
electrical equipment. is feature, the result of co-ordination with other rms, should
be a great aid to the exibility of British Railways operating arrangements.
The principal data of the locomotives
Wheel arrangement .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Bo-Bo
Maximum weight in working order. .. .. .. .. .. .. .. .. .. .. .. 75 tons
Maximum axle load in working order. .. .. .. .. .. .. .. .. .. .. 18¾ tons
Diesel Engine HP at continuous rating .. .. .. .. .. .. .. .. .. .. 1,160 hp at 750 r.p.m.
Maximum tractive eort .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 40,000 lbs.
Continuous tractive eort.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 21,300 lbs.
Speed at continuous tractive eort and full engine output .. .. 15 mph
Maximum speed.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 75 mph
Driving wheel diameter.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 45 inches
Length over buers. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 50 6 inches
Distance between bogie centres .. .. .. .. .. .. .. .. .. .. .. .. .. 28
Bogie wheel base . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 8 6 inches
Fuel oil capacity (engine and boiler) .. .. .. .. .. .. .. .. .. .. .. 630 galls.
Water capacity for boiler .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 600 galls.
Locomotive Structure
In order to achieve a light construction, the weight carrying properties of the vehicle
are shared between the underframe and a girder structure to which the body sides are
attached. Bung and draw loads, however, have not been neglected and the
underframe is designed for bung loads of 200 tons. In the rst place, the locomotives
are being tted with double buers and a central screw-link coupling. Provision,
however, has been made for the later addition of automatic central couplers.
e underframe consists of two longitudinals, each consisting of two standard
channel sections. ese channel sections are placed back to back and the intervening
space is covered top and bottom by plates, so forming ducts for the traction motor
ventilating air, thereby avoiding fragile sheet metal ducts and considerably simplifying
the underframe arrangement.
e longitudinals form the foundation for the four-point mounting of the engine
generator set. ey are tied together by the two main transoms which carry the bogie
pivots and by other substantial members. e side girder frames are axed to these
transoms and tied together at the top by steel sections which also form the roof
framing. Cables and pipework have been kept away from each other on opposite sides
of the locomotive. e cables are laid in a duct outside the main longitudinal member
and this duct is covered in on all sides. e pipework is tted in a similar manner.
Despite the presence of the side girder structures, access to the interior is
satisfactory. Due to the slim in-line engine, there is provision for moving from end to
end of the locomotive on both sides of the diesel engine, and inspection doors are
tted on each side of the engine room to facilitate handling of equipment at overhauls
such as exchange of fuel injectors, lter elements and so forth.
For major overhauls, there is a large removable section of the roof through which
a complete engine generator set can be installed and removed. is section has a
small hatch for removal of engine cylinder heads and pistons, and there are also
smaller hatches through which the boiler auxiliary equipment and control gear can
be installed or removed.
A sealing plate tted to the underframe receives any leakage from the engine
room or boiler compartment. is drains into a centrally placed spillage tank, which
may be emptied from time to time. In addition, clean fuel spillage is kept completely
separate and is ducted back to the main fuel tank.
All air coming into the engine room is ltered through 2-inch deep Air Maze
lters located in the body sides. e whole of the engine room therefore becomes
a clean air compartment from which air is drawn for the traction motor blowers,
engine, main generator and all auxiliary equipment. In addition to the engine
room ltration, which is of a type designed for low air resistance despite severe
contamination, the engine has its own high eciency lter of the Vokes oil wetted,
bonded hair type. In accordance with the usual method adopted by Sulzer, the hot air
exhausting from the generator is expelled downwards out of the engine room so that
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there is no recirculation. Special care has been taken in sealing all possible sources
of leakage of unltered air in the engine room and in this respect, the air-tight design
of the radiator ducting on both sides of the panels is especially noteworthy.
Bogies
e bogies are of welded and riveted construction with box frames. ey are of the
spring bolster type and are equalised. e primary suspension consists of two sets of
coil springs arranged on each equalising beam each of which is damped by a shock
absorber. e bolster rests on the spring plank through two nests of coil springs, the
motion of which is also damped by shock absorbers. e spring plank is hung from
the bogie frame by four swing links which are pin jointed with hardened steel bushes
at the top and knife edged at their connection to the spring plank at the bottom.
Cab Equipment
e cabs are most spacious. e two doors are placed behind the driver’s and
assistant’s seats and there is sucient room to move freely in and out without
disturbing the crew. Comfortable adjustable seats are provided and the controls and
indicators present a very neat appearance. e driver is confronted with the
minimum of instruments, namely speedometer, load ammeter, Duplex vacuum
gauge, main reservoir, pressure gauge and straight air brake gauge.
A cab heating and ventilating device combined with a screen demister is tted.
Fresh air is blown by an electrically driven blower through heating elements fed
from the engine cooling system and can be controlled by the driver. e unit can be
used for blowing cool air in exceptionally hot weather.
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Engine and Accessories
e engine is the Sulzer 6LDA28, pressure-charged, six cylinder, four stroke in-line
engine rated at 1,160 hp at 750 rpm with a testbed one-hour rating of 1,276 hp at
750 rpm. Five of the engines of the 30 locomotives are being supplied from Sulzer
Brothers Works in Switzerland, but the majority are being built to Sulzer orders at
Messrs. Vickers-Armstrong’s Works at Barrow.
e design needs little further description. e crankcase and cylinder block
with their cast steel transversals welded to mild steel top and side plates and the
crankcase and engine generator mounting as an integral structure, are well known.
e forged aluminium pistons are tted with oil cooling channels behind the
rings in order to ease their working conditions. Precision bearings are tted in the
cranksha main bearings and big ends. ese are of a trimetal type developed by
Sulzer Bros. and consist of a steel backing, coated with copper lead with a top layer
of so bearing metal. is top layer is think enough to last the life of the bearing.
Shims are not used in these bearings and no hand tting or adjustment is required.
C.A.V. fuel injection equipment is tted. It has been made in consultation with
Sulzer Brothers and the Sulzer double helix type plunger, by which means both the
injection point and the cut-o can be controlled, is retained.
Accessibility of the engine components has always been a prime Sulzer
consideration and the British Railways engines incorporate improved fastening
arrangements for all covers to reduce the work entailed in releasing them, whilst
retaining the characteristic oil tightness and cleanliness of the engines.
Cooling water circulation, lubricating oil priming and fuel transfer pumps
are all driven by a single traction type auxiliary electric motor. us they can be
operated independently from the engine, enabling circuits to be primed before
starting the engine and providing even cooling of the water jackets, pistons and
bearings aer stopping.
Lubricating oil is cooled in a Serck heat exchanger by the cooling water. e heat
exchanger ts closely and neatly to the engine and thus no major oil piping leaves the
engine. e main advantage of heat exchanger cooling is, however, quick warming
up and good temperature control.
Tanks are tted under the radiators to drain the water from the panels as soon as
circulation ceases, and in this way freezing of the elements in cold weather is avoided
and quick warming up by complete bypass of the radiator is possible.
e air ltering scheme is described earlier in this article. Detailed attention has
also been paid to liquid ltration. Besides Knecht ne wire wound self-cleaning
strainers in both the fuel and lubricating oil system, there is a full ow Purolator
paper type fuel lter and a high capacity Fram waste packed bypass lubricating lter
taking approximately 20% of the total ow to keep the oil in good condition.
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BTH Electrical Equipment
Generator and Auxiliary Machines
e generator unit comprises three machines – a main generator, an auxiliary
generator and a dierential exciter. e main generator is a single-bearing, 12-pole,
separately-excited, self-ventilated machine solidly coupled to the diesel engine and
mounted on an extension of the engine underbed. It is a 735 kW machine rated at
750/525 Volts, 980/1400 Amps, 750 rpm. e armature is built on a fabricated
cylinder, a stub sha being provided at the bearing end. e drive from the engine
is taken on the full diameter of the cylinder, ensuring great torsional rigidity and
freedom from the eect of cyclic variation of torque. e BTH ‘Pollock Type’
commutator construction is used which obviates the possibility of loosening of
segments in service.
e brushes are split in pairs with equalised pressure on each brush. Pressure is
applied through an insulated roller so that it is impossible for the brush arms to
carry current from the top of the brush. Brush pressure is adjustable and compensated
between the two half brushes.
e auxiliary generator is an 8-pole, separately-excited, constant-voltage
machine of 50 kW, 110 Volts, 500/750 rpm; the armature is mounted on an extension
of the sha of the main generator. In order to reduce the length of the set to a
minimum, the auxiliary generator is accommodated partly within a recess in the
main generator commutator.
e exciter is a 4-pole machine with separate, self and dierential series excitation
windings. It is mounted upon an adjustable platform on top of the auxiliary generator
frame, and is belt-driven from the main generator sha extension. e output of the
exciter is controlled by the engine load regulator.
Traction Motors
e four nose-suspended, series-wound traction motors drive through single-
reduction gearing. Each motor as a one-hour rating of 209 hp, 490 Volts, 375 Amps,
505 rpm and a continuous rating of 213 hp, 525 Volts, 350 Amps, 560 rpm. ey
are force ventilated by two separate blowers which are driven by a single 12.2 hp,
110 Volt, 2,600 rpm motor; each blower provides ventilating air to a pair of motors.
e motors are axle hung and nose-suspended by Metalastic chevron rubber
units which whilst providing a so vertical suspension, eect a large measure of
lateral control of the motor irrespective of side movement of the axle, thus reducing
ange wear and improving the riding of the locomotives. e gear wheels are of
resilient construction, and consist of a hub and toothed rim connected through
rubber bushes which cushion mechanical shocks due to accelerating forces and
track irregularities.
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Control Equipment
e control unit is mounted in a dust-tight compartment in the body of the locomotive
at the generator end of the engine room. It is thus convenient for cable runs and at the
same time away from engine piping. On this control frame are located all the
contactors, relays and switch devices. Separate contactors are provided in each motor
circuit. e reverser is of the butt contact type, having silver-faced main contacts; it
is electro-pneumatically operated.
e driver’s control equipment comprises a master controller and instrument
panel, in each cab, together with alarm identication panel, engine instrument panel,
lighting switch boxes and re alarm unit.
e battery is contained in four pull-out boxes suspended from the underframe.
With the engine running, it oats across the 110 Volt supply from the auxiliary
generator, controlled by a Brown Boveri sector-type regulator.
Control Scheme
e characteristic of the combined generator-exciter unit is that of the well known
three-winding generator. e exciter had a dierential series winding which carries
the main traction current, and also a separately excited winding which is externally
controlled both by the driver’s controller and the automatic load control. Due to the
low value of excitation current in this small machine, small control devices can be
employed. e shape of the characteristic is the familiar drooping curve, the
excitation being proportioned so that there is a denite maximum limit to the current
which can be delivered to the traction circuit at standstill, and so that at this point, the
demand on the engine is less than its rated output. e section of the characteristic
which intersects the contact HP curve of the engine is articially controlled by
varying the separate eld of the exciter by means of a rheostat.
is rheostat is controlled by an oil servomotor which is incorporated in the
engine governor. is arrangement automatically varies the generator loading so that
it agrees with the predetermined engine output at any particular engine speed. e
four traction motors are connected in parallel across the main generator with two
stages of motor eld weakening.
Complete control of the main traction equipment is obtained by a self-lapping air
valve operated from the master controller. On moving the power handle away from
the ‘O’ position, the load regulator rst runs up, increasing the excitation and therefore
tractive eort. At a certain point, the main engine characteristic is reached and
thereaer, engine speed and power rise together, until the full rated HP is reached.
e scheme covers the control of tractive eort at starting and of locomotive power
aerwards, all without the use of ‘notching’ contactors.
Maximum tractive eort is reached at a very low engine speed so that racing the
engine to start the train is completely unnecessary. Field weakening is introduced in
stages initiated by the generator load regulator.
Protective Devices
e protective devices provided on this locomotive are of two types: (1) apparatus
for the safety of the locomotive in trac; (2) apparatus to protect the engine and
transmission equipment.
Under category 1 there is the deadman’s pedal with its corresponding push-
button on the opposite side of the cab, which permits the driver to cross the cab to
observe signals. Also air-operated switches are provided to prevent the locomotive
from being driven until there is sucient compressed air and vacuum to operate the
locomotive and train brakes. In addition, the new BR type of automatic train control
is tted.
Protective devices in the second category include provision for the engine to be
automatically stopped in the event of low cooling water or lubricating oil pressure,
and the appropriate latched relay operates on the identication panel of the locomotive
aected. An ‘engine-stopped’ light at the driving position indicates if any one engine
is stopped when running in multiple unit. is alarm also serves as a guide when
starting engines on locomotives couple in multiple, since the start push-button is
merely held depressed until the ‘engine-stopped’ alarm becomes normal.
Earth leakage causes the earth leakage relay to operated and the traction circuit to
be opened. Provided the earth fault has cleared, the relay can be reset by moving the
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3. Spotting features
For what, outwardly, what looks like a relatively homogenous group of the
locomotives the BR/Sulzer 1,160hp Type 2s encompass a surprisingly large
number of design changes or in-service detail variations. In order to enhance
your experience of our model, it is a fascinating exercise to outline some of
these dierences to illustrate the extraordinary lengths we have gone to. As
with any machine that had a service life of more than two decades there are
numerous minor changes. We will faithfully re-create all signicant changes,
and most of the smaller ones too, over the course of our release programme.
Bodyside air intakes
ere was some experimentation, within the pilot scheme build of 20 locomotives,
on the number and position of the small bodyside air intakes/lters. ese were
adjusted several times on the rst built (D5000) over the rst few months and, on
D5018/9, the layout even changed between sides. is is the rst model ever to
represent these variations. Standardisation, with fewer grilles, was maintained
throughout the production build and thus we have modied our tooling irreversibly
to match, eectively making our early pilot scheme models limited editions.
Radiator grilles
e rst half dozen machines had the bodyside radiator grille fabricated with one
deeper horizontal bar designed to accommodate the original pin strip livery (which
did not nd favour aer D5000). ese grilles were sometimes replaced or moved
onto other locomotives during the course of repair or overhaul. Both early and later
types of radiator grille are modelled.
Axlebox variation
Ten of the pilot scheme locos (D5010-9) were initially tted with ‘Athermos’ plain-
bearing pressure lubricated axleboxes. ese were large and distinctive assemblies
with bolted cover facings featuring the ‘Athermos’ brand name. e variation was
not perpetuated, with SKF roller bearings being adopted as standard. is interesting
variation is modelled where appropriate.
Silencer and exhaust port
A major problem became apparent not long aer introduction, with a number of
serious res in the roof area at the No. 2 end. e expansion box and resonator
silencer - which receives the hot exhaust gases from the turbocharger before venting
to the atmosphere - was being contaminated by oil leading to pyrotechnics and
explosions. A modication programme took place at Derby Works during the
mid-1960s to remove both components and add a new ‘straight-out’ exhaust stack,
driver’s controller to ‘o’ but a ag on the relay remains displaced until reset by
hand, thus indicating to the shed sta that an earth fault has occurred at some time
during service. In the event of traction motor blower failure or high water
temperature, the alarm indication is made at the driving position by an indicator
light, whilst a latched relay operates on the alarm identication panel of the
locomotive aected. When the engine ‘alarm’ light indicates trouble, the driver can
then go back to the engine compartment where a detailed indicator shows which
actual part of the apparatus is giving trouble. A wheel slip indicator light is tted at
each driver’s position. All indicator lamps glow dimly under normal operating
conditions but light up brightly under fault conditions.
Brakes
e brake equipment is of the Oerlikon type manufactured by Davies & Metcalfe
with Westinghouse brake cylinders. Air brakes are supplied for the locomotive and
provision is made for vacuum braking on the train. e brake control is vacuum
operated and an air brake is applied to the locomotive through a proportional valve.
In addition to this system, there is an independent air brake for the locomotive. A
trigger on the independent air brake valve enables the locomotive brake to be
released whilst still holding the brake on the train and is of value when coupling or
uncoupling.
Each bogie carries four 8-inch Westinghouse horizontal brake cylinders
incorporating a slack adjuster. Air for the locomotive brakes and for air operated
control equipment is provided by a Westinghouse DVC2 compressor. Vacuum for
the train brakes is provided by two Westinghouse 4V110 exhausters.
In addition to conventional sanding, the Swiss anti-slip brake, already well
established on the Continent, makes its rst appearance in this country. is greatly
assists heavy starts under bad adhesion conditions without the wear caused by sand
in the locomotive running gear and in points. Separate operating switches are
provided for the anti-slip brake and for sanding.
Steam generator
A Stone-Vapour boiler is installed having a capacity of 1500 lbs of saturated steam
per hour. e apparatus is automatic and fully protected.
...
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placed above the power unit. Dependent on period/livery, the models either display
the original resonator silencer with its raised, curved surface and circular exhaust
port, or a later plated-over roof section and simplied direct outlet.
Frame fairings
Aesthetics, it could be argued, was not of high importance with these Derby Type 2s.
However, one concession was the contoured fairings that enclosed the longitudinal
frames and their associated pipe and cable runs at solebar level. Hinged in sections,
to give access for maintenance, they were subject to regular damage and became a
hindrance. ey were removed at half-life overhaul, leaving the frames with a very
utilitarian appearance. e fairings were dropped completely from the later Class 25s.
Underslung fuel and water tanks
Weight limitations and operational requirements led to several arrangements of
underslung fuel and boiler water tank. e diesel fuel tank, at the No. 1 end, was
reduced in capacity (and physical height) from 630/546 to 520/500 gallons whilst the
water tank was reduced in capacity (and length) from 600 to 450 gallons both from
D5050. In addition, sight glasses were quickly superseded by circular gauges. On the
freight only locomotives employed on Tyne Dock-Consett iron on workings, and in
later years when boilers were isolated, the water tanks were removed completely.
Bogie cab footsteps and sandboxes
Both two and three-rung bogie footsteps exist. e former (original) design was
restricted to pilot scheme and early production locomotives before the arrangement
was changed due to experience (the steps were too widely spaced to making climbing
awkward). A revised shape of sandbox, to simplify fabrication, was also introduced
with the later Class 25. Component swaps and repairs quickly led to the mixing of
these designs to the extent that some locos sported dierent sandboxes at each end!
Bodyside footsteps and battery isolating switch cover
As a direct result of spreading overhead electrication, the bodyside footsteps/hand
holds were plated over to prevent access to the roof. At the same time a small cover
was placed over the coolant overow outlet adjacent to the roof scavenger fan. e
exterior battery isolating switch cover was found to work open due to vibration and
so was secured by a more foolproof locking bar. All these in-service modications
are included where necessary, most commonly on blue-liveried locos.
Boiler pressure relief valves and roof water filler cover
Several arrangements of steam pressure relief valves exist (linked to equipment
routing and dierent workshops) in segments cut out of the roof, above the boiler
compartment. Our models allow for these variations to be represented. e hinged
cover for the roof-mounted boiler water ller point is also included as a separate
etched item. is component was quickly dispensed with in service due to its fragility.
High-level air pipes
In 1964, the Tyne Dock-Consett iron ore trains were taken over by Type 2s working
in multiple, replacing steam traction. NER-based locomotives D5102-11 were
allocated to this role having been modied with an air compressor and control
equipment in place of the boiler. e water tanks and steam heat piping was removed
and new high-level air pipes installed on the front ends in order to provide a supply
for the compressed air-operated hopper doors on the wagons. e distinctive pipes
remained in situ when the locos were transferred away aer the trac ceased. If you
wish to model these locos, contact us for a special upgrade pack, containing revised
underbody details and a pair of high-level pipes.
Removal of front end doors
As was convention at the time, these locomotives were built with front end gangways
intended for crew access when running in multiple. It was found to be a little used
feature and the doors were soon locked out of use. As a constant source of dras and
water ingress, they were rst covered by strips on some Scottish-based machines
before a prolonged Works programme of removal and re-sheeting took place. Derby
and Glasgow Works had diering techniques, the latter choosing to reposition the
middle marker lights and discs on the centre-line. Not all locos were treated before
withdrawal, many retaining the front end doors.
Headcode boxes and headlights
It was not until well through the build that a redesign of the front end took place with
the adoption of train reporting number apparatus (headcode box) on the cab roof.
e simplied front end, albeit still with doors, was now devoid of headcode discs
and marker lights leaving just two low level tail lights. is change took eect from
D5114 onwards. A batch of these locomotives was allocated to Scotland and was
subsequently tted with a pair of headlights on the central nose section at each end.
SLW Class 24 Operating Manual Page 23Page 22 SLW Class 24 Operating Manual
4. Model description
is model will give you many years of reliable operation if it is handled with
care and periodically inspected and serviced. It has been created as a working
replica for adult modellers and collectors, and should not be regarded as a toy.
e standard model is intended to operate o conventional 12V direct current,
supplied from a model railway controller. A decoder blanking plug is tted.
Digital sound versions feature a ZIMO decoder connected via the PluX22
(NEM 658) connection and require a DCC control system for full functionality.
Fine detail - handle with care
e model comprises 350 individual components, all of which have been painstakingly
hand assembled. A range of dierent materials have been utilised including injection-
moulded plastics plus cast and photo-etched metals. e high number of parts is in
contradiction to the recent trend towards simplication, and is a direct result of the
quest for greater detail. Many parts are fragile and if the model is handled, it should
be done so with great care. We cannot be held responsible for any damage during use.
Designed for smooth operation
A die-cast zinc alloy metal chassis has been employed for superior adhesive weight
and houses our smooth-running ‘Black Cat’ ve-pole motor. e centrally-mounted
motor, mated to two brass ywheels, supplies movement via carden shas running
to both bogies. e tolerances and free-running of any drive-train have a dramatic
impact on responsiveness. Our requirement has therefore resulted in a low-friction
specication which comprises worm reduction drives feeding spur gears linked to all
axles. ese are housed in a machined metal gearbox, designed to avoid any twisting
and binding problems that are common with deformed or less-than-rigid plastic
components. All axles run in lightly lubricated stepped brass bearing bushes.
Minimum recommended radius
e wheelsets nominally provided are set for ‘OO’ (16.5mm) gauge track. e model
will run over commercial track systems down to a minimum radius of 16 inches
(400mm) but, due to the nescale RP25 wheel prole, more satisfactory running will
be achieved over curved track formations of a larger radius. e use of this locomotive
is not recommended on ‘vintage’ or coarse-scale trackwork.
Good haulage capability
e mechanism provides a haulage capacity that meets most demands. Remember
that the rolling resistance of stock varies considerably. Because of the deliberate
omission of ‘traction tyres’, please do not expect performance to match that of older
models. Tests have shown this model to be easily capable of hauling over 14 modern
bogie carriages on level track and seven carriages up a 4% gradient.
5. Display and set-up
e model is supplied in its own display case which also acts as secure packaging
during transit. is case has been provided for collectors who may wish to display the
locomotive as part of a larger collection or perhaps as an individual executive desk
feature. You will note that by the use of three angeways, this base accepts wheels set
to ‘OO’, ‘EM’ or ‘P4’ gauges.
To extract the model from the case, li o the transparent cover and remove the
plastic blister support and protective polythene sheet. Undoing the two long mounting
screws from the underside of the base will released it from the plinth.
As supplied (in display mode), the model has fully detailed buerbeams with
representations of the screw-link couplings and various brake hoses, control cables
and ladders. To run with the UK ‘tension lock’ system, please t the additional parts
as supplied with the packaging: e coupling plugs into a right-angle NEM 362
pocket that, in turn, is seated in the coupling apparatus behind the buerbeam. A
hidden kinematic movement system (in the chassis) is employed that automatically
extends the coupling as the vehicle enters a curve.
Note: To work eectively and reliably it may be necessary to remove or cut away any
pipes or detail that restrict free movement of the ‘tension lock’ coupling.
SLW Class 24 Operating Manual Page 25Page 24 SLW Class 24 Operating Manual
ere should be no need to access the interior of the model in normal use. Access
to the chassis, motor and printed circuit board is gained by removing the bodyshell.
ere are four small securing lugs moulded on the inside of the bodyshell, positioned
above the inner axles on both sides. ese interface with similar positioned rebates
in the die-cast chassis’ sides. Gently ease the body apart from the chassis along its
lower edge at these points - this can be done by inserting some home-made ‘wedges’
formed from plastic sheet or chopped-up hot drink stirrers (if you don’t have access
to long female ngernails!). e chassis can then be gently drawn out by gravity or a
exerting a light downward separating force. Fit and use the original mounting screws
for this purpose - do not be tempted to hold the fuel/water tank area.
Note: Extra caution is needed on the models tted with solebar fairings. It is recommended
these parts are carefully removed rst by easing downwards with a thin blade. Because
of the number of components involved, the fuel tank area will not take a separating force
without breaking, and should not be used for purchase when removing the body.
6. Additional detailing parts
For the benet of modellers who wish to modify the look of their locomotives we
have provided a number of optional ttings. ese parts are included in bags found
under the display case base. As well as the previously mentioned UK ‘tension lock’
couplings, in-line brake blocks for ‘OO’ gauge wheelsets are also included - please
see Chapter 9 for more information. Cantrail boiler water ller point covers are also
issued along with a vacuum timing reservoir and coupling bash plate (locates behind
buerbeam). Some spare lamp irons are provided in case of damage in use.
In addition, we have provided a selection of headcode discs in open, closed-down
and closed-up arrangements. You can use these to change the headcodes displayed
on your model. e legs need to be bent back 90 degrees and inserted in the location
holes in the cab front.
See diagram, right, for a simplied explanation of the headcodes carried during
the 1962 to 1968 period. A revision was made in 1968 following the elimination of
steam and to reect the increased use or air-braked stock and block trains.
If you are looking for an easy guide to what the dierent disc combinations
indicate, then we recommend a visit to: www.2d53.co.uk/Headcode/headcodeC.htm
Express passenger, newspaper,
light engine going to assist,
or ocer’s special not requiring
to stop in section.
Ordinary passenger train,
mixed train, branch passenger
train (where authorised by the
Regional Operating Ocer).
Parcels, sh, fruit, meat, milk, horse
box, cattle, or perishables train
composed of vehicles conforming to
coaching stock requirements.
Express freight train brake piped
throughout and with the automatic
brake operative on not less than 90%
of the vehicles. Max. speed 55mph.
Express freight train partly tted
with the automatic brake operative
on not less than 50% of the
vehicles. Max. speed 50mph.
Express freight train partly tted
with the automatic brake operative
on not less than 20% of the
vehicles. Max. speed 45mph.
Express freight, livestock,
perishables, or ballast train
not tted with automatic brake.
Max. speed 40mph.
rough freight, livestock,
perishables, or ballast train
not tted with automatic brake.
Max. speed 35mph.
Freight, mineral or ballast stopping
at intermediate stations. Branch
freight train (where authorised by
the Regional Operating Ocer).
Light engine(s), or engine with
not more than two brake vans.
e ‘full house’ headcode -
reserved for the Royal Train.
SLW Class 24 Operating Manual Page 27Page 26 SLW Class 24 Operating Manual
7. Running-in and maintenance
Even though every model has been tested extensively in our factory, performance
characteristics will gradually improve with regular use. e locomotive should
initially undergo a ‘running-in’ period to allow all moving components to seat
properly. It is suggested that the model is le to run for at least 45 minutes in each
direction at a selection of dierent speeds. Lubrication has been applied to the gear
train and bearings during manufacturer.
Occasional cleaning and light re-lubrication using non-hazardous plastic
compatible oils and grease is suggested. Light oil should be used for axle and motor
spindle bearings, with a more viscous grease (such as Molykote EM50L) for the
worm and gear train. Good electrical continuity is essential for smooth and reliable
operation. Inspect the model before use and carefully remove any deposits, debris or
u that may have accumulated. As well as ensuring the rail head is clean, it is
imperative that an uninterrupted supply to the motor is maintained by regular
cleaning of the wheel treads and the wiper pick-ups acting on the back of the wheels.
is can be achieved using a pipe cleaner soaked in lighter fuel or similar solvent. A
touch of electrically conductive lubricant can be applied to the clean pick-up faces.
Avoid using abrasive materials which will scratch the wheel surface and make
cleaning more dicult.
To make this less of a chore, why not imagine you are running a real railway where
locos need to visit the shed in order to be given booked maintenance aer running
for a set period. A regular ‘A-exam’ could comprise wheel cleaning, whilst a more
occasional ‘B-exam’ might include inspection and cleaning of the wiper pick-ups,
lubrication of moving parts, checking wheelset back-to-back measurements, etc.
8. Lighting and printed circuit board (PCB)
We know, through experience, that frustration has been encountered by many
modellers in trying to adapt or modify lighting circuits and printed circuit boards to
suit their specic needs. To this end, a simple but advanced design is utilised, capable
of handling both DC (analogue) and DCC (digital) control. It additionally incorporates
provision for sound by providing direct connections and space for a twin-speaker
system. For smooth and reliable operation, electrical continuity is paramount so you
will not nd any unsoldered or ‘wiper’ connections here. All links with the main board
are made using industry-proven JST miniature plugs and sockets, which have the
added advantage of making swap-outs much quicker and simpler.
For DC users we’ve have stuck to our ‘keep it simple’ philosophy and have
avoided over-complication and retained robustness by avoiding constant brightness
circuits for the light emitting diode (LED) lighting. e lights are designed to be
prototypically dim (marker and tail lights on the actual locomotive are only 25W
bulbs). However, some anti-icker capability has been built in. As delivered, the DC
model will also illuminate the cab interior in direction of travel. is can be disabled,
if required, by unplugging the relevant LED connections wires on the main PCB.
e special DCC blanking plug incorporates a simple system for those wishing to
slightly reduce the top speed of the locomotive. By removing the ‘000’ SMD resistor
‘bridges’, the motor supply will travel via series diodes which reduces the maximum
voltage available by 0.7V (one) & 1.5V (both) without aecting the lighting.
For DCC users, the PCB comes in to its own, having been specically designed to
take advantage of the latest developments in this eld. e newest PluX22 (NEM658)
decoder connection is utilised to take maximum advantage of the 10 function outputs
provided by ZIMO’s advanced sound decoders. e decoders provided for this model,
manufactured specically for us, have the PluX22 index pin (pin 11) in place as an
active output (FO8) and we have described these decoders as PluX22e (enhanced).
Each group of lighting, at each end of the model, is allocated to an individual
Function Output, always with a Common (+) line nearby, so that operation can be
made completely independent of each other, a feature that we have taken advantage
of in our DCC-tted models. is also allows you to re-programme congurations
if so required. Our DCC-equipped models feature optional lighting modes with a
default of forward markers only (as if hauling a train). At the touch of a button, the
tail lights can be switched on for a ‘light engine’ movement. Similarly, the cab interior
light can be activated in one movement. Illumination throughout the model is
provided by miniature surface mount warm-white or red LEDs with in-line
protective current limiting resistors. Using ZIMO soware, the lighting has been
programmed with ‘so’ on/o to mimic tungsten lament bulbs ‘brightening up’
and ‘dimming down’.
SLW Class 24 Operating Manual Page 29Page 28 SLW Class 24 Operating Manual
As well as the previously described twin loudspeaker connections, the main PCB
incorporates three other features new to British market. e rst of these is the
provision of two energy storage capacitors wired in parallel. Giving a total value of
1360f, they are linked to the ZIMO decoder’s dedicated circuitry connections
providing full ‘stay-alive’ and ‘smart-stop’ capability. See the Chapter on DCC Sound
for a more detailed explanation of these special features.
A further three-pin connector also provides for a direct link to the decoder’s
Switch Input, Common and Ground, allowing an input device, such as reed switch
to be attached. e most obvious use of this is to attach a Hall Sensor allowing
automatic magnetic triggering of a sound function, and in fact, a warning horn has
been set as the sound default in our programming for just this occasion. (See Chapter
11 for further details and add-on kit). Wire routing holes have been provided in the
chassis, below the motor, for those who wish to undertake this advanced modication.
Additionally, four solder pads are provided for DCC specialists who wish to
make a direct connection to the decoder’s serial user standard interface (SUSI) for
control of further devices such as servos.
For reference, the Function Outputs are wired to the following lighting circuits on
DCC equipped models:
Output Lighting circuit PluX22e pin
FOf No. 1 end: Marker lights (white) 7
FO1 No. 1 end: Tail lights (red) 16
FO3 No. 1 end: Headcode box 2
FO5 No. 1 end: Headlights 20
FO7 No. 1 end: Cab interior/engine room 22
FOr No. 2 end: Marker lights (white) 13
FO2 No. 2 end: Tail lights (red) 18
FO4 No. 2 end: Headcode box 19
FO6 No. 2 end: Headlights 21
FO8 No. 2 end: Cab interior/engine room 11
Note: Not all function outputs/lighting circuits may be used on every model version.
For instance, a pilot scheme Class 24 will obviously not have alpha-numeric headcode
box or twin headlight illumination circuits tted. Redundant outputs may, of course, be
reprogrammed and utilised for other features such as electromagnetic couplings, smoke
generators, etc. if so wished (and if space can be found).
9. Wheels and bogies
In another rst for a British model, and in response to the demands of those using
employing more accurate track gauges, we have supplied factory-tted ‘nescale’
wheelsets in one of three dierent gauges. e wheels incorporating the distinctive stress-
relieving holes around their circumference. In best practice, turned wheels are mounted
on steel axles with insulating collars that also act to limit lateral movement. Dierent size
collars and axle lengths are used dependant on the gauge. Brass bearings lock into the
machined cast metal gearbox to minimise wear and maintain tight tolerances.
In an eort to keep the wheels looking as accurate as possible within the compromises
dictated by ‘OO’ (16.5mm) and ‘EM’ (18.2mm) gauge, the widely-used NMRA
RP-25/110 wheel contour standard has been adopted, avoiding unnecessary deep anges.
ese wheelsets have been extensively tested on numerous commercially available
Code 75, 83 & 100 track systems.
For exact-scale ‘P4’ (18.83mm gauge), a much ner wheel prole is adopted that
complies with published standards from groups working in this gauge.
e brake rigging and blocks align with ‘P4’ wheelsets by default. Optional ‘OO’
versions of the brake blocks are provided separately and can be tted, if required, to give
a better look when using 16.5mm gauge wheelsets. is will require disassembly of the
bogie and is only recommended for the experienced.
Back-to-back dimensions are set at 14.50mm (‘OO’), 16.50mm (‘EM’) & 17.75mm
(‘P4’) at our factory but should be checked before and regularly during use, and
adjusted if necessary to obtain optimum running characteristics. Some experienced
users will wish to make small changes to these measurement to suit their own
trackwork requirements.
Should you wish to change to a dierent gauge aer purchase, this is possible by
removing the keeper-plate on the underside of each bogie’s gearbox and simply
replacing each wheelset. e plastic keeper-plate is held in place by a large clip at each
end and two smaller clips each side inboard of the axles. Gently lever them over their
retaining lugs. e wheelsets can be extracted and replaced by hand. Make sure the
gear wheels are in alignment and that the bushed brass bearings are rmly seated down
in the axle recesses. Wipe pick-ups can be adjusted to apply light pressure to the rear
faces of the wheels. Replacement wheelsets to suit all three track gauges are available
from us for an additional charge.
SLW Class 24 Operating Manual Page 31Page 30 SLW Class 24 Operating Manual
10. Digital sound operation
Introduction
Installing sound into a model locomotive signicantly increases its cost. We believe
it should, correspondingly, increase its value. In our experience, too many sound-
tted models fall well short of this expectation. We understand the frustration many
experience using restricted operational features usually provided with sound-tted
models so we were determined to give you the freedom and the tools to decide how
your model’s movement and sounds interact.
We set ourselves the challenge of providing the ‘best ever’ sounding Class 24
model, incorporating as much user-control as possible. In both these regards we
believed our aim has been achieved, thanks to cutting-edge technology and the most
up-to-date recording methods and equipment. is model is notable for being the
rst ready-to-run diesel to be factory-tted with Austrian-made, high-performance,
DCC decoders from ZIMO Elektronik.
Close co-operation with ZIMO’s development team in Vienna has provided new or
enhancedcontrolfeaturesideallysuitedtoBritishdieseloperations.Ourunderstanding
of the prototype and the soware has enabled us to provide you with a sound project
able to simulate all normal operational sound and movement combinations. is
installation allows more realistic sounds to be deployed across a wider range of
operating conditions. e sounds have been programmed in such a way that you,
the user, may change the way that the sounds respond to your driving style or needs.
is avoids the need for reprogramming and additional costs that would imply.
e sound output of this model was judged to be the most authentic in a audio test,
which included a number of enthusiasts and professional railwaymen. Credit for this
must go to Paul Chetter, who is widely regarded as the leading authority on ZIMO
programming. anks to unprecedented recording access, his skill, enthusiasm and
attention to detail have created an exclusive sound project that will satisfy the most
ardent ‘Baby Sulzer’ fanatic. e distinctive ‘spluttering’ exhaust notes of the Sulzer
power unit have been faithfully recreated and will be instantly recognisable.
A truly successful project is one that captures the essential characteristics of the
locomotive. is includes how the model responds to control inputs, the relationship
between track speed and engine sounds, the balance of individual sounds within the
mix and how the installation aects the nal results.
Please spend a few moments to read these notes which have been produced so that
you may obtain the maximum satisfaction from this revolutionary ZIMO sound
scheme. Some of the new features will not operate to their full potential if you use 14/28
speed steps. If at all possible, please ensure you use 128 speed steps to take maximum
advantage of these controls. Individual locos may require some ne tuning that you can
achieve with your DCC controller.
Sound specification
e model is tted with a ZIMO MX645 PluX22e DCC sound decoder, tuned to a
pair of high-end miniature 8 loudspeakers housed in custom-designed plastic
enclosures mounted within the die-cast chassis. is arrangement was devised to
provide the best possible audio experience from the restricted space inside the
model. e decoder is also connected to a pair of energy storage capacitors.
e MX645 is a technologically-advanced chip, which is highly regarded because
of its impressive specication that includes a 40kHz ‘silent’ drive with back-EMF
sampling. Despite its relatively small size, it packs an incredibly powerful 3W audio
amplier and an accommodating 1.2A continuous (2.5A peak) current rating. All
features, including up to ten function outputs, switch input and SUSI connections
are available for customisation. is model is congured to run ‘straight from the
box’ with ZIMO’s legendary silky-smooth motor control.
Our loudspeakers were originally designed for portable consumer devices, such as
smartphones and tablet computers where high quality sound is required but physical
space is constrained. It is the world’s rst miniature speaker featuring advanced silicon
membrane technology optimised for extended low frequencies. e result is superior
bass performance over that expected from such a small device.
Premium ZIMO decoders have special on-board circuitry, described as an ‘electronic
ywheel’, to manage capacitors used as external power supplies. ese are the stay alive
energy storage capacitors already included on the model’s PCB (or the replacement
SC68 supercapacitor upgrade). Once the decoder is attached, via the PluX connection,
it does all the charging and monitoring automatically.
ZIMO’s ‘Smart Stop’ system is unique and highly sophisticated. It is designed to avoid
stopping on an electrically ‘dead’ spot. As the loco is slowing down, just before it stops
completely, the decoder monitors the availability of power from the track. If it detects
poor supply - a speck of dirt for example - it prevents a nal stop. Instead it keeps the loco
moving at minimal speed, using power from the connected capacitors if necessary. e
track conditions are continuously assessed and as soon as favourable power conditions
return, the decoder will stop the loco. e capacitors will be recharged during the
dormant period ready to supply power again when required. ese movements are
very small and the monitoring so frequent that under normal operation it is almost
impossible to see it happening. However, it has the potential to transform running
characteristics and provide reliable starting in less than perfect conditions.
e system should not be regarded as an alternative to good permanent way
cleaning and maintenance, but it can be a real help if the wheels are not entirely clean
or the trackwork is uneven. e circuit assists in preventing unscheduled stops, sound
interruption and ickering lights. It can make the dierence between successfully
crossing a dead frog or stalling on the points.
SLW Class 24 Operating Manual Page 33Page 32 SLW Class 24 Operating Manual
How a real locomotive operates
To simulate the sounds of a diesel-electric locomotive successfully, you will need
some idea of how and why they sound as they do. e most important aspect to
know is that the diesel engine itself does not propel the loco directly. e engine
drives a generator, which provides the electrical power for the traction motors. It
is these electric motors that actually turn the wheels via gears. is means there is
no linear correlation between diesel engine speed (or sound) and track speed, and
explains why some models sound so unrealistic.
For example, with engine idling, there is sucient power to move a light locomotive
(without train). Releasing the brakes is oen all that would be needed to move o.
Put a few hundred tons on the hook, and the loco will need a lot more power to get
its train moving, even slowly. at’s two dierent ‘power’ sounds needed for the same
speed. Now imagine a heavy train on an upward incline. It may be going slowly, even
decelerating, but the engine will be providing maximum power. On the descending
gradient, the engine may well be at idle, with the loco travelling at speed or even
accelerating, eectively being pushed downhill by the weight of the train behind it.
In the real world, these eects are created by gravity, mass and inertia. In the
‘model world’, sound projects have to simulate them. We have gone to great lengths
to bring you the correct sounds and necessary controls to get as close as possible.
It’s now down to your skill and knowledge to simulate any eventuality!
Prototypical brake application
On a real locomotive, acceleration, speed and deceleration are under control of the
driver. He will use his experience of the locomotive type, the train weight and
knowledge of the route to anticipate the control movements required to achieve the
required performance and safety. Deceleration is oen achieved by reducing power
only, allowing the locomotive to ‘coast’ down to lower speeds. Typically, the brakes
are only used to ne tune this rate of deceleration or make a halt at a specic point.
At other times, strong braking will be required, even at high speed, such as in an
emergency brake application.
A feature notably lacking in all other programmable decoder brands with
British sounds, is the ability to apply a variable braking force to increase the rate of
deceleration when desired. is makes stopping a heavy train at a signal or station
platform more dicult than it is on a real loco. Without brake force, the locomotive’s
dynamics are only partially modelled. ere is no point in having the sound of brakes
being applied if the rate of deceleration is unaected!
Working closely with the decoder manufacturer’s soware engineers, we have
designed and incorporated a revolutionary new ‘Brake Force’ feature. e objective
is to simulate the real driving experience as closely as possible. It will require you to
SLW Class 24 Operating Manual Page 35Page 34 SLW Class 24 Operating Manual
Special control features
We have included several special control features which you may use to modify the
way the sound samples play. ese may be used individually or in combination to
provide greater realism and thus enhanced pleasure. You do not need to employ them
as your model (as supplied) will simulate normal driving completely automatically,
but we strongly recommend you at least try them. ese features eectively render
the old, cumbersome, ‘manual notching’ techniques obsolete.
: e sound is switched on/o and the engine started
and stopped with the F1 button. Starting a real Class 24 from cold rst requires the
lubricating oil to be pressurised and the coolant circulated. An electric pump, called
a ‘combined pump set’, performs these functions. Your decoder has the combined
pump set sounds assigned to the F14 button, which will operate prototypically with
the engine sounds o. is allows you to choose when to use it and the required
duration. You can then choose a ‘cold’ start, where the engine res aer a bit of
cranking, or a quicker, ‘warm’ start where the engine res immediately.
Cold start: Engage F5 button before using F1 to start the engine.
Warm start: Disengage F5 before using F1 to start the engine.
In both cases, aer the engine has started engage or disengage F5 depending on
the driving style you wish to use (see ‘light engine mode’, overleaf). To simulate a
failed start in either case above, operate F1 then disengage it immediately.
: As supplied, the decoder will output the sounds of a Class 24
with a loaded train. Aer running the combined pump set and starting up, the loco
will stand with the diesel engine ticking over at idle. e sounds will respond to the
throttle control in the following way:
From standstill, increase to Speed Step 1 and the brakes will release, before the
engine will power-up slightly to get the loco moving. With increasing Speed Steps,
further ramp-ups in engine power will be initiated until the nal high-speed running
sounds begin. e transition points between power bands will depend upon your
actual model. e sounds will spool-down at similar points on deceleration.
‘’: A new feature, unique to ZIMO, has been incorporated.
Open the throttle gently... the engine note will rise and fall appropriately and the
acceleration will simulate that of a heavy train.
Open the throttle more quickly... e engine will ramp-up to full power and the rate
of acceleration will be increased accordingly.
With the throttle fully opened... (then reduced if required) the loco will accelerate
three times more quickly than normal.
Never before has a sound project simulated the variety of driving styles so accurately.
change your DCC driving technique but has the feeling of ‘putting you straight in
the driver’s seat’! Here’s how it works:
For optimum control and convenience, the feature needs to be assigned to a
non-latching (or momentary) F-button. On many non-European designed DCC
controllers, the only momentary button is F2. Some, like NCE PowerCab have a
designated separate key which operates F2 from a dedicated Horn/Whistle button.
e sound project has been constructed to take these limitations into account, so the
Horn/Whistle button becomes the Brake Key. (Don’t worry, the horn will not blow
when you brake!). Other brands, such Lenz, allow you select the type of operation -
latching or momentary - for each F-button, for each locomotive.
With the locomotive running at mid-speed, reduce the throttle (speed step)
setting to zero. e loco will slowly begin to decelerate and the engine sounds will
spool down directly to idle. Next, make a brake application with F2. A short ‘dab’
will produce a short air release sound and a modest increase in deceleration. You
can think of this as ‘speed trimming’. is can be repeated if required, and is entirely
prototypical in operation. A longer application will produce a longer air release
sound and a slightly greater rate of deceleration.
Holding the F2 button down will produce a long air release sound and the loco
will perform an emergency stop. In other words, brake force increases with time
and maximum deceleration rate is achieved immediately prior to coming to a halt.
Automatic brake squeal will accompany the nal moments before halting. e button
can also be used to simulate ‘brake dump’ testing when at a stand.
e brake may also be operated during deceleration between dierent speeds, for
example approaching a speed restriction. In this case, reduce the throttle to required
lower setting. e engine sound will change according to the features described
earlier, so may result in a dierent power sound rather than engine idle (but you
may wish to force coast using F6). To increase the rate of deceleration, use the F2
brake as before, and the speed of the loco will be ‘trimmed’ to exactly the selected
speed and not below. So there are now no excuses for a signal passed at danger or
exceeding a speed restriction! Remember also that prior to rst use of the day, and
at anytime deemed necessary for safety, the eectiveness of a locomotive’s brakes
would be tested.
If F2 is le on a ‘latched’ button, and le on by mistake, the engine sounds will
respond to the use of the throttle, but the brake release sound will not play (as brakes
have not been released) and the loco will not move since it is being ‘held’ by the
brakes. is is a bit like trying to drive o in your car with the hand brake still applied!
Please note that real locomotives do not ‘stop dead’ even during an emergency stop.
To reect this, an emergency stop will be reasonably abrupt but not sudden. If your
DCC controller is equipped with a ‘panic button’ to avert imminent catastrophe, this
will still operate as usual, and will have more immediate eect than the brake button.
SLW Class 24 Operating Manual Page 37Page 36 SLW Class 24 Operating Manual
: Characteristics of an uncoupled or ‘light’ locomotive will be
quite dierent from when it is has a heavy train in tow. It will be capable of accelerating
and decelerating much more quickly whilst the power required to accelerate and
maintain speed will be signicantly reduced. ese changes cannot be successfully
simulated simply by changing inertia settings which, in any case, would have to be
adjusted when the loco is halted every time it deposited a train.
With a single press of F5, you can now alter the driving characteristics to that of
‘light loco’. Inertia is automatically, reduced, the thresholds at which the sounds change
are adjusted and the samples playing are amended. With small throttle increments the
idle sound will be held for the rst portion of driving, enabling slow yard movements
(or similar) to be made without engine ‘revs’ increasing. Alternatively, large throttle
movements will produce a ramp-up for a few seconds initially, aer which the engine
sounds will return to the level appropriate to the new speed.
is feature reduces inertia and momentum, as well as delaying automatic engine
power increases until higher track speeds are reached. F5 can be operated at any
speed to give another way in which the engine sounds may be instantly modied.
Note: is feature works best if you switch F5 ‘on’ or ‘o’ whilst the engine sounds are
playing in idle. Once switched, you can leave it that way, but any further change should
also be made with the engine sound again playing the idle sound. Just to be clear, the
actual speed is unimportant, but the engine sound must be idling. You can achieve this
in several ways as discussed earlier.
: In common with most British designs of locomotive,
the Class 24 power handle does not have xed power level positions or ‘notches’, but
is continuously variable. ere is, however, a tactile ‘notch’ to indicate selection of an
‘on’ position. ere are also markings to show approximate power levels as follows:
: In this position, the engine is idling only (and powering ancillaries etc.).
: Engaged prior to movement, this position connects the main generator to the
traction motors. is additional load causes the idling engine note to speed-up very
slightly to compensate. In layman’s terms, the loco is now ready to move. Indeed, on
level track, if the brakes were released, the loco could move slowly without additional
power needing to be applied.
: Approximately a quarter of the power available. is is typically enough
to li a light train on level track or for low-speed yard movements and shunting.
: Approximately a half of total power. is is typically used for light trains on
slightly adverse gradients, or to provide an acceleration surge
-: Approximately three-quarters of total power available. is is
enough to li a heavy train on level track and the maximum normally required
when running ‘light engine’.
: We’ve allocated F6 as the ‘Coast’ button. With this single
action you can dramatically aect the engine sounds being played. It will produce
dierent eects depending upon the speed of the loco, including when it is stationary.
When in motion, it will spool the engine sounds down to ‘idle on’ without aecting
the track speed. Use this to simulate ‘shutting-o’ prior to slowing to a halt or for
many other ‘coasting’ scenarios (for example, a heavy train on a downward grade).
Release the button and sounds will increase in power, according to the speed
currently selected.
Try leaving the F6 button ‘on’ aer the loco has halted, and keep it on even when
driving o. e loco can now creep around with just an idling engine sound, great
for pottering around the shed or yard. Release it aer speed has built up, however,
and the engine will instantly burst into higher power, the precise sound depending
upon the track speed and the status of F5 & F7 buttons.
Note: F6 takes precedence in its inuence over sounds; if engaged, it will always cause the
engine sounds to remain at or spool down to ‘idle’. However, it has no impact on inertia.
ere is also another way of ‘coasting’ without the need for any button presses. No
matter what actual speed your model is travelling at, or which engine power sound is
playing, reducing the throttle by 10 Speed Steps (of 128) will spool-down the engine
to idle, whilst the loco will continue travelling with a gradually reducing speed. is
coasting sound will continue until you accelerate; at which point the sounds will
change to those relevant to the current speed.
- ( ): In most circumstances, the driver of a
locomotive will maintain the correct track speed by varying the engine power to
match the load, gradient and signal indications. Sometimes this will be by ‘coasting’
with the engine at idle and at other times by just reducing the power to a lower level.
Following the instructions outlined above will reliably simulate the former.
However, if instead of engine idling you would rather hear a slightly more powerful
note, you can do so at any time by decreasing the current speed by just one step on
your controller. e automatic ZIMO ‘notch back’ feature (sometimes known as
step-down) will instantly transition the sound playing to the next lower power band.
For example, if the loco is playing ¾ power sounds, reducing speed with your throttle
by one Speed Step will cause the sound to immediately spool-down to the sound
of ½ power. If in ¼ power, it will spool down to idle. If you operate with 128 Speed
Steps selected, this will be achieved without any appreciable change in track speed.
(Continued deceleration will not give further changes in sound until the speed
settings reaches the normal threshold which has been set in the project).
An increase of one Speed Step, or more, will immediately ramp the sound back up to
the higher power. So, at any given speed, it is possible, to toggle between two power
bands without perceptibly changing the speed. Talk about ne control!
SLW Class 24 Operating Manual Page 39Page 38 SLW Class 24 Operating Manual
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