Great Central Models Robinson GCR Class 8B Atlantic LNER C4 User manual

Page 1 GCR Class 8B
Page 1 GCR Class 8B
Great Central Models
Robinson GCR Class 8B Atlantic
(LNER C4)
Version 1.2 February 2013
Assembly Instructions Revised July 2014
Catalogue #GCM005
This kit is optimised for P4 and EM standards. The kit was designed by “Great Central Models” as part of an
expanding range of Great Central Railway locomotives.
Great Central Models Ltd is registered as a Private Limited Company - 7355519
Further details - www.greatcentralmodels.co.uk
Enquiries to [email protected] or via the contacts page on the web site
The picture above is for illustration only, it is actually a 7 mm model painted and finished by a very well known artist, whose
writings on the subject are well worth reading. Also worthy of note is the newly released book by John Quick, “Robinson’s
Locomotive Liveries on the Great Central Railway”.

Page 2 GCR Class 8B
Page 2 GCR Class 8B
Robinson GCR Class 8B LNER C4
The Class 8B was a trial build of a 4-4-2 soon after Robinson decided on a big engine policy. While impressed by the work done
by Churchward at Swindon, he seems to have adopted a cautious approach so decided to build 4 locomotives, essentially with
all the major features the same, but the Class 8C as a 4-6-0 and the Class 8B as a 4-4-2 Atlantic. 6’ 9” coupled wheels were fitted.
The work was done by Beyer Peacock and was based on the earlier 4-6-0s, the so-called “fish” engines which were Class 8 under
the Great Central way of categorising locomotives.
In principle, the rear end of the Class 8B was designed so that it could be converted easily to the Class 8C but it was the ‘Atlantic’
design that prevailed.
All were built between 1903 and 1906 by Beyer-Peacock (7), North British Loco. Co. (12), and at Gorton (8) with saturated steam
boilers. The only difference was really the fire grate, in the first build it was rather shallow, matching the Class 8C. Once the
decision had been made to stick with the 8B design rather than the 8C, a deeper fire box was fitted. They were withdrawn over
a period from 1939 until 1950, having been replaced by the B17s, but mainly during 1948-1950. None of them received BR
numbers, their replacement meant that none were re-painted or re-numbered.
Superheating was started in 1912 and continued right up to 1936 - no rush then!
As with the other Robinson locomotives, chimneys were a varying feature. The classical GCR chimneys were not approved by the
LNER because of the loading gauge issues (in common with most of the GCR classes) so were replaced initially by the LNER
flower-pot version. Later a pseudo-GCR chimney was fitted. Use the “13 ft Gauge” column below as a guide to when this
happened, generally it was a lot later than other Robinson classes. Flattened or angular domes were used at various times, the
angular domes seemed to appear during WW 2. The movement of the whistle from the cab top onto the boiler happened for
the same reasons of loading gauge As always, a good picture is the best guide, provided the dating is accurate!
For guidance, according to RCTS data and Yeadon Vol 13:-
Manufacturer Built Withdrawn GCR # Superheated LNER 1924 LNER 1946 13 ft Gauge
Beyer, Peacock 12/1903 11/1950 192 9/1920 5192 (10/1925) 2900 (8/1946) 5/1937
Beyer, Peacock 12/1903 11/1950 194 10/1925 5194 (10/1925) 2901 (6/1946) 1/1938
Beyer, Peacock 7/1904 4/1949 263 6/1926 5263 (4/1924) 2902 (6/1946) 8/1938
Beyer, Peacock 7/1904 6/1949 264 7/1921 5264 (2/1924) 2903 (9/1946) 9/1937
Beyer, Peacock 7/1904 12/1947 265 9/1920 5265 (1/1925) 2904 (8/1946) 5/1937
Beyer, Peacock 7/1904 10/1943 266 5/1921 5266 (5/1922) 2905 5/1938
Beyer, Peacock 7/1904 11/1947 267 9/1920 5267 (2/1925) 2906 (3/1946) 3/1939
N.B. Loco. Co 10/1905 12/1947 1083 1/1921 6083 (9/1924) 2907 (6/1946) 4/1937
N.B. Loco. Co 10/1905 11/1950 1084 8/1929 6084 (7/1925) 2908 (6/1946) 7/1937
N.B. Loco. Co 10/1905 11/1950 1085 1/1925 6085 (1/1925) 2909 (6/1946) 1/1925
N.B. Loco. Co 10/1905 2/1949 1086 8/1914 6086 (2/1924) 2910 (6/1946) 10/1937
N.B. Loco. Co 10/1905 11/1944 1087 9/1920 6087 (12/1925) 2911 11/1937
N.B. Loco. Co 10/1905 8/1949 1088 12/1926 6088 (11/1924) 2912 (9/1946) 12/1936
N.B. Loco. Co 11/1905 4/1947 1089 6/1920 6089 (10/1924) 2913 (11/1946) 10/1937
N.B. Loco. Co 11/1905 11/1939 1090 3/1914 6090 (10/1924) 8/1936
N.B. Loco. Co 11/1905 3/1948 1091 4/1925 6091 (4/1925) 2914 (6/1946) 9/1937
N.B. Loco. Co 11/1905 6/1949 1092 3/1921 6092 (7/1925) 2915 (10/1946) 8/1936
N.B. Loco. Co 11/1905 11/1948 1093 11/1927 6093 (9/1925) 2916 (9/1946) 6/1937
N.B. Loco. Co 11/1905 5/1949 1094 1/1936 6094 (2/1924) 2917 (8/1946) 7/1937
Gorton 2/1906 12/1950 260 2/1935 5260 (12/1925) 2918 (8/1946) 5/1938
Gorton 3/1906 11/1950 261 1/1927 5261 (12/1925) 2919 (8/1946) 2/1937
Gorton 4/1906 2/1948 262 4/1925 5262 (12/1925) 2920 (8/1946) 1/1937
Gorton 5/1906 4/1948 358 5/1920 5358 (12/1925) 2921 (8/1946) 3/1937
Gorton 6/1906 6/1948 360 10/1920 5360 (12/1925) 2922 (8/1946) 12/1936
Gorton 7/1906 2/1949 361 3/1912 5361 (12/1925) 2923 (8/1946) 10/1937
Gorton 6/1906 1/1948 362 3/1928 5362 (12/1925) 2924 (8/1946) 3/1937
Gorton 8/1906 4/1949 363 2/1921 5363 (12/1925) 2925 (8/1946) 2/1937

Page 3 GCR Class 8B
Page 3 GCR Class 8B
Additional Notes
LNER Numbering - there were huge variations in how LNER numbering was applied. Sizes varied, location carried, style varied,
sometimes just ‘NE’, sometimes still with the GCR cab side plate and the letter ‘c’ added to the LNER number, sometimes on the
tender but mainly on the cab once the LNER got themselves sorted out.
Photographs should be consulted when deciding what number to have. Of course in GCR days it was all rather simpler.
Locomotives could have a carriage heater connection at the front as they became used on passenger trips which would mean
that a heating pipe should also be added to the tender.
Smoke box handles - for this class the wheel arrangement was kept throughout their lifetime.
There are more versions of the chimneys and domes than catered for by the kit. The original chimney was of a much finer
appearance and rapidly failed in service.
Ramsbottom 2 column valves were originally fitted and a branching arrangement used for the traditional 4-column appearance.
These were originally uncased but casing was added later. Ross valves replaced the Ramsbottom valves during superheating.
Tail rods on the cylinders were removed before grouping but I have no dates for this, it seemed to happen over a longer period
than other GCR classes, but before grouping. On super-heating a ‘snifting’ valve was fitted behind the chimney. At the same
time the ash ejector was fitted on the right of the Smoke Box.
Centre steps were removed before the grouping, at speed they could ‘whip’ and potentially hit the connecting rod.
Livery was perplexing. Originally in full GCR green regalia, they soon reverted to lined black and then the LNER painted them
green again until WW 2, when they all became black again. Under LNER management, the beading was always unpainted and
usually unpolished.
Tenders when built for 192, 194 were the GCR 3,250 gallon version but these were soon replaced by the group standard with
plated sides.
As with all models from this era, the best thing a modeller can do is refer to published literature such as
Ÿ“Locomotives of the LNER Part 3A” from RCTS
Ÿ“Locomotives of the Great Central Railway” by E. M. Johnson
ŸPhotographs from various collections - usually available at shows such as Scaleforum and Scalefour North
Ÿ“Yeadon’s Register of LNER Locomotives - Part 13”
These locomotives, known as the “Jersey Lilies” ranged far and wide and could be seen as far away from GCR rails as Plymouth
and Weston-Super-Mare, even running a slip coach at one stage. They ended their days doing light duties on the BR Eastern
Region. Their visits to Plymouth are a good excuse to put a “Green, with rivets”, next to a GCR Class 8B, “Green, without rivets”
Important Note
This kit has been designed for P4 or EM standards. Alternative parts have been designed into the brass and nickel silver frets.
There are plenty of spare parts for the smaller items. Considerable additional work will be needed to build this kit to ‘00’
standards. Remember that ‘00’ and EM wheels will cut into the boiler space. For EM modellers care must be taken not to
increase the upward movement of the wheels if sprung or compensated by filing out the axle slots in the frames. If the kit, when
built, has a lot of side play then even the P4 version will find the wheels hitting the boiler. In all cases the boiler can be ground
out to clear this.
Notes on the kits and constituent parts
The etched parts in this kit have been designed using a CAD program (TurboCAD 18.2) to ensure accuracy when fitting the parts
together. Included in these notes are:-
ŸA list of etched and cast parts
ŸA list of additional and optional parts
ŸDrawings of the etch fret

Page 4 GCR Class 8B
Page 4 GCR Class 8B
ŸDetailed step-by-step instructions with the drawings extracted from the CAD originals
The original CAD drawings were prepared from GA drawings obtained from MOSI in Manchester and scaled at 12” to 1’. During
the design process a number of compromises had to be made (such as the frame widths) because of the materials and parts
available to the modeller and the P4 and EM standards. These compromises were used to draw a full size CAD drawing which
was then used to provide the instructions and construction drawings and the final etch parts. The etch parts of the drawing
were scaled down very accurately to produce etches for the 4 mm modeller.
The kit prototypes were built by the designer. The first trial etch was used as a feasibility project and to write outline
instructions. The second test etch was used to test the assembly, write instructions and produce the assembly diagrams as well
as a viable model. A modeller familiar with etch brass kit construction should be able to build an accurate model if these
instructions are followed, generally as written. However, fine-scale modellers being who we are, other ways of building the kit
will be tried!
The Instructions
More years ago than I care to remember I was involved in validating and writing Master Work Sheets for the Royal Air Force.
These were sets of instructions that had to be followed to the letter by technicians world-wide even though they may never
have met that particular piece of equipment before. Deviations were never permitted to the technicians – given that the
machines being tested were vital to safe flying – and any permission to be deviant granted by senior authority was subject to a
very close monitoring process.
However, senility and pending obsolescence have taken their toll – nobody is perfect – so if you find anything in these
instructions you feel to be wrong it will be examined closely and amended where appropriate. Likewise, with the measurements
of the parts, if there is something which you feel may be wrong then, please let me know. It would be nice if this was supported
by drawings, or copies of drawings with time stamps if possible. Photographs are useful as well. But be warned, the available
drawings are neither consistent nor accurate if my research means anything at all and there were so many cosmetic changes
made to these locomotives over nearly 50 years that photographs without a date stamp must be treated with some caution.
Things to note
In a few areas there are alternative ways of doing things. While there are traditional etched springs on Sheet 3, for this kit the
centre springs have been printed using 3D CAD technology. They are fitted to the horn blocks. Note that these are heat sensitive
and will melt as quickly as white metal castings. The etched or printed springs mean that the wheels can also be removed for
‘servicing’.
Continuous Springy Beams (CSBs) may be fitted - they seem to be all the vogue these days. I am a little uncomfortable with the
idea for a complex wheelbase such as a 4-4-2 and prefer to stick with the prototype idea where each axle is sprung by itself.
Short handrail knobs are used for the spring mounts. EM and ‘00’ modellers may use frame blanks to remove the need for
springing.
Stephenson’s Valve Gear would have been visible only by looking very carefully, for this engine. Extra parts are provided so you
can experiment with the way it fits together. If you are tempted to try this then please do remember not to solder the parts in
situ ‘after’ you have fitted your plastic centred wheels. The valve gear may be fitted in working order or as a very loose fit on the
centre axle. In the second case they will be visible but will not move except around the axis of the axle.
The Stephenson’s Valve Gear is tricky to get working well and may be left out. The rest of the engine will still look good when
finished and painted.
The builder will find an array of brake parts on the fret. While 3D brakes are an option and remove the possibility of shorts while
fitting closely to the wheels, they are vulnerable to handling errors. However, there are ways to strengthen them with the etch
base parts, or the builder may use etch parts only.
Rear and centre frame spacers - those supplied on the etch are to scale and may be fitted if desired - you can create frame
spacers which are a good representation of the originals with their strengthening brackets but these are difficult to see when
the model is completed. In practice the rear spacer construction was used to steady the front of the fire box but this may be
omitted without weakening the whole chassis. P4 and EM versions of these spacers are supplied together with some generic
spares. These are not standard widths though. Use the spares in appropriate places if you do not need the scale spacers or wish
to add your own parts for additional electrical pick-up.
There is substantial current collection capability in the tender. I was persuaded not to have pick-ups in the locomotive since they
would detract from the scale frame spacers and the valve gear and since there is plenty of space in the tender with or without
the optional DCC chip this may be a good option. The two wires for the motor may then represent the vacuum and heating
pipes.

Page 5 GCR Class 8B
Page 5 GCR Class 8B
The part numbers and descriptions (where space permits) are half etched on the frets as near to the parts as sensible and match
the description that appears in the Parts List. These annotations will appear in the form “212”, or “223,224” or 213-217” or 218-
225+3”. Where something like “212EM” appears on the fret then that is the EM version of a part that will also have a P4
(unlabelled) part on the fret. Where the “+” appears in the part number it shows that additional parts have been included and
the number following shows that 3 additional parts are on the fret. This allows for two possibilities
a) losing very small parts in the carpet after cutting them from the fret
b) practising the assembly in cases where some difficulty may be expected
Also on the fret there are a couple of blocks on which to practice your skill at pushing out rivets. Try these first to test the
consistency of your efforts. Refer to photographs to check if these parts were actually riveted early in life, Robinson abhorred
‘proud’ rivets and there is some photographic evidence to show that they may not have been used in the early days, even at the
bottom of the smoke box.
The instructions also use the Part Number and Full Description. This may seem a little pedantic but can help where there may be
some uncertainty. I also list all parts separately and do not group sets of parts together (i.e. Springs Qty 7) so that you will find
the parts list will show each layer in a built up assembly as an individual item.
Assembly Instructions
You may also find it easier to drill out all the locating holes while the parts are still within the main etch, and even to assemble
some of the parts together - simply because this helps to hold at least one of the parts firmly in place.
Do not use force at any time, you are likely to bend the parts beyond repair. The tabs and slots are designed to be a semi-tight
fit and on occasion a little easing with a strip of wet & dry sandpaper may be needed, especially on the slots in the smaller parts.
If needed, where parts fit into a slot, very lightly dress the mating edges with a fine file. Most slots are 2 mm long and the edge
strips on the etches may be used to ease them out a little if needed.
Unless otherwise stated, the folds are all done with the half etch on the inside.
TAGS are on the fret and hold the individual parts in place when the fret is etched. TABS are on the parts to fit into SLOTS in the
corresponding parts. In many areas on the fret TAGS have been arranged so that they fit onto TABS solely to help minimize any
possible damage to the component when the TAGS are removed since the TABS will all in the end be invisible.
Do not confuse TAGS and TABS and file off any TABS!
It may be easier to do a number of preparatory jobs before removing parts from the main etches. There are a few rivets that
may have to be pushed through from the rear of some parts, such as the main frames. The smoke box wrapper was flush riveted
when built but as the LNER super-heated the locomotives they would normally have been replaced by the usual, highly visible
rivets. Front buffers sometimes had rivets added after superheating but not necessarily at the same time. The smoke box
wrapper may also have had further rivets added as well as the smoke box front around the door, which seemed to have
happened in the late 1930s and early 1940s.
As always, if you are really keen on authenticity then the best thing to do is to examine a photograph of the engine you are
modelling.
Decision time
The kit has been designed to use frame spacers that approximate to the frames on the original engines, which means that
stiffeners are also added to the inside and outside of the frames. Should you decide that adding these scale spacers is a step too
far since they will be almost invisible then alternative spacers are included for P4 and EM. Or the builder may decide to provide
his own set of spacers, especially if there are concerns about side play for small radii curves.
Cosmetic spring mechanisms are provided. These are removable using screws for those of us who like to be able to remove the
wheel sets easily.
Sufficient parts are included to make this kit to either P4 or EM standards. Because the EM wheel back-to-back is a little smaller
than P4, the spacers for EM are narrower and the frames will not have the distinctive kink at 4’ 0” from the front of the frame.
Do not mix up the P4 and EM parts since you will find there a world of pain. Remember that EM parts are identified on the fret
with a suffix ‘EM’ after the Part Number.
The kit as designed will go around a 1250 mm radius curve before the bogie wheels hit the frames. A tighter turning circle will
mean that the bogie frames have to be cut back to allow the bogie wheels further side play and they are half-etched on the
inside as a guide. Note also that for something like a 1000 mm radius that the rear inside of the cylinders will need trimming.

Page 6 GCR Class 8B
Page 6 GCR Class 8B
Soldering
I use ‘Nealetin’, a liquid solder with its own flux. This allows very close control of the initial solder join. Most initial joints will be
secure using this (or a similar liquid solder). Motion parts should be soldered with a higher temperature solder. Once you are
convinced things are square then it is possible to run a small fillet of solder along critical joins by first priming with a little
‘Nealetin’.
I have never used lead free solder for making models.
Square Frames
There are a couple of mechanisms, neither of which I have used, which have been acclaimed for the ease with which they
permit a square frame to be built. While these are expensive to start, many modellers have sung their praises.
Under Etched parts
On occasion some parts may be a little under etched. The individual frets have outer frames which are the same width as the
vast majority of the slots (2 mm) - just use a short section of this to free up any dubious slots. In any event it is always wise to
prepare parts using a very fine file to remove any bits of ‘cusp’ left from the etching process, before assembly.
Health & Safety
Experienced modellers will know all this already but -
ŸThe frets are made from 12’ brass and 15’ nickel silver. They are fragile and the edges are sharp. Take care when assembling
and especially when drilling out holes. Rotating brass (which tends to grab drill bits, especially near the end of their cut) or
nickel silver will cause a lot of skin and tissue damage if the drill sticks and tears. For preference use a hand drill or pin
chuck.
ŸSoldering entails the use of toxic materials such as lead and acid flux. Observe the warning notices that come with these
products and especially use adequate ventilation. Wear suitable eye protection where needed.
ŸSolder also gets very hot when melted, as do the parts when heated to solder them together. Take care to hold parts
carefully with insulating material where needed and to let them cool properly before handling. This is especially true if
annealing parts so they can be bent into shape more easily. It is also true where several layers may have been used to build
up an assembly.
ŸWhen painting, ensure proper ventilation, especially if using a two part etch solution. Some of these carry hazardous
chemicals.
ŸOn a few occasions there will be a wire across the frames or bogie soldered at both ends. Do not be tempted to cut this
after assembly with the normal wire cutters, this will force the frames apart and cause some damage. Use something like a
triangular file or a disc cutter to make the first cut!
Note on bending parts with half etched lines
Tighter bends may be achieved as follows if thought to be necessary (notes extracted from some thoughts by Will Litchfield).
1. Deepen the fold line with a triangular 4 cut needle file till a witness line shows though to the other side.
2. Hold the etch on a flat surface with a your trusty steel rule along the fold line.
3. Run a craft knife blade along under the etch to start the fold on it way.
4. When the edge stands well way from the flat surface, use another steel rule to complete the fold.
You get a sharper bend this way, because a of step 1 and it is accurately placed on the centre of the fold line.
Notes on wheel choices
The frames on this kit are set to a design width of 16.15 mm for P4 so that with cusp removal on the spacers approximately
16.00 mm is the final frame width. This is slightly less than some kits, but more than other kits, especially those which were
designed for the ‘00’ market and then had options added for the finer scale gauges of ‘P4’ and ‘EM’. To this width must be
added the outer flange of the horn blocks, which will vary depending on horn block supplied - the ones supplied are from
Markits.
For the fine scale gauges, side play can be an important issue especially where small radius curves of less than 1200 mm are to
be tackled.

Page 7 GCR Class 8B
Page 7 GCR Class 8B
There are three wheel sets available, from Alan Gibson, Ultrascale and Exactoscale. For P4, the Alan Gibson wheels have a rear
boss which is 0.5 mm deep. This will impact side play, especially for P4 modellers and less so for EM modellers. This rear boss
should be removed from Alan Gibson wheels.
Potential purchasers in the fine scale gauges are urged to consider these points. There are, as always, strategies to ameliorate
such issues. Further reading on these points are in :-
Side Play Supplementary Notes
Design Notes
Both of which are available on the web site at www.greatcentralmodels.co.uk on the ‘instructions’ page.

Page 8 GCR Class 8B
Page 8 GCR Class 8B
Locomotive Chassis
0.015’ 0.375 mm Nickel Silver
Locomotive Frame
1. Frame Left - Sheet 1
2. Frame Right - Sheet 1
3. Front Buffer Beam - Sheet 1
4. Front Buffer Beam Overlay - Sheet 1
5. Rear Buffer Beam - Sheet 1
6. Rear Buffer Beam Overlay - Sheet 1
7. Cylinder Spacer Front - Sheet 1
8. Cylinder Spacer Rear - Sheet 1
9. Cab Base Support - Sheet 3
10. Firebox Base - Sheet 3
11. Smoke Box Base - Sheet 3
12. Rear Frame Spacer - Sheet 3
13. Rear Frame Spacer Brace - Sheet 3
14. Rear Frame Spacer Stiffener Left - Sheet 1
15. Rear Frame Spacer Stiffener Right - Sheet 1
16. Centre Frame Spacer - Sheet 3
17. Centre Frame Spacer Stiffener Left - Sheet 1
18. Centre Frame Spacer Stiffener Right - Sheet 1
19. Valve Guide Support Spacer - Sheet 3
20. Valve Guide Support Spacer Stiffener Left -
Sheet 1
21. Valve Guide Support Spacer Stiffener Right -
Sheet 1
22. Slide Bar Support Left - Sheet 3
23. Slide Bar Support Right - Sheet 3
24. Buffer Support Left - Sheet 1
25. Buffer Support Right - Sheet 1
26. Sandbox Left - Sheet 1
27. Sandbox Right - Sheet 1
28. Brake Cylinder Support Left - Sheet 1
29. Brake Cylinder Support Right - Sheet 1
30. Guard Iron Left - Sheet 1
31. Guard Iron Right - Sheet 1
32. Buffer Mount - Sheet 1
33. Buffer Mount - Sheet 1
34. Coupler - Sheet 1
35. Coupler - Sheet 1
36. Rear Buffer Housing Plate - Sheet 1
37. Rear Buffer Housing Plate - Sheet 1
38. Footplate Fixing Bracket - Sheet 2
39. Front Buffer Beam Draw Bar Plate - Sheet 1
40. Front Buffer Beam Draw Bar Plate - Sheet 1
41. Rear Buffer Beam Draw Bar Plate - Sheet 1
42. Fire Box Brace - Sheet 1
43. Drag Link - Sheet 1
44. Drag Link - Sheet 1
45. Drag Link - Sheet 1
46. Firebox Right - Sheet 1
47. Firebox Left - Sheet 1
48. Bogie Mount - Sheet 3
49. Cylinder Head - Sheet 3
50. Cylinder Head - Sheet 3
51. Cylinder Head - Sheet 3
52. Cylinder Head - Sheet 3
53. Safety Loop - Sheet 1
54. Safety Loop - Sheet 1
Brakes
55. Brake Frame Mount - Sheet 1
56. Brake Frame Mount - Sheet 1
57. Brake Frame Mount - Sheet 1
58. Brake Frame Mount - Sheet 1
59. Brake Frame Mount - Sheet 1
60. Brake Frame Mount - Sheet 1
61. Brake Pull - Sheet 3
62. Spare
63. Spare
64. Brake Pull Centre Bracket - Sheet 3
65. Brake Pull Centre Bracket - Sheet 3
66. Brake Pull Front Bracket - Sheet 3
67. Brake Pull Front Bracket - Sheet 3
68. Vacuum Cylinder Link - Sheet 3
69. Brake Mount - Sheet 3
70. Brake Mount - Sheet 3
71. Brake Mount - Sheet 3
72. Brake Mount - Sheet 3
73. Rear Wheel Brake Mount - Sheet 3
74. Rear Wheel Brake Mount - Sheet 3
75. Brake Mount Top Layer - Sheet 3
76. Brake Mount Top Layer - Sheet 3
77. Brake Mount Top Layer - Sheet 3
78. Brake Mount Top Layer - Sheet 3
79. Rear Wheel Brake Mount Top Layer - Sheet 3
80. Rear Wheel Brake Mount Top Layer - Sheet 3
81. Brake Shoe Base - Sheet 3
82. Brake Shoe Base - Sheet 3
83. Brake Shoe Base - Sheet 3
84. Brake Shoe Base - Sheet 3
85. Rear Wheel Brake Shoe Base - Sheet 3
86. Rear Wheel Brake Shoe Base - Sheet 3
87. Brake Shoe Top Layer - Sheet 3
88. Brake Shoe Top Layer - Sheet 3
89. Brake Shoe Top Layer - Sheet 3
90. Brake Shoe Top Layer - Sheet 3
91. Rear Wheel Brake Shoe Top Layer - Sheet 3
92. Rear Wheel Brake Shoe Top Layer - Sheet 3
93. Brake Cylinder Link - Sheet 3
94. Brake Cylinder Link - Sheet 3
95. Rear Brake Pull - Sheet 3
96. Spare
97. Rear Brake Pull Tag - Sheet 3
98. Rear Brake Pull Tag - Sheet 3
99. Small Brake Pull - Sheet 3
100. Small Brake Pull - Sheet 3
101. Actuator to Brake Lever - Sheet 3
102. Actuator to Brake Lever - Sheet 3
103. Brake Lever - Sheet 3
104. Brake Lever - Sheet 3
Coupling Rods
105. Coupling Rod Left Front - Sheet 2
106. Coupling Rod Left Front Overlay - Sheet 2
107. Coupling Rod Left Boss Front - Sheet 2
108. Coupling Rod Left Boss Front - Sheet 2
109. Coupling Rod Left Boss Front - Sheet 2
110. Coupling Rod Left Boss Front - Sheet 2
111. Coupling Rod Right Front - Sheet 2
112. Coupling Rod Right Front Overlay - Sheet 2

Page 9 GCR Class 8B
Page 9 GCR Class 8B
113. Coupling Rod Right Boss Front - Sheet 2
114. Coupling Rod Right Boss Front - Sheet 2
115. Coupling Rod Right Boss Front - Sheet 2
116. Coupling Rod Right Boss Front - Sheet 2
Connecting Rods
117. Connecting Rod Left - Sheet 2
118. Connecting Rod Left Overlay - Sheet 2
119. Connecting Rod Right - Sheet 2
120. Connecting Rod Right Overlay - Sheet 2
121. Connecting Rod End Overlay - Sheet 2
122. Connecting Rod End Overlay - Sheet 2
123. Connecting Rod End Overlay - Sheet 2
124. Connecting Rod End Overlay - Sheet 2
Slide Bars
125. Slide Bar Left Upper Main - Sheet 1
126. Slide Bar Left Lower Main - Sheet 1
127. Slide Bar Overlay - Sheet 1
128. Slide Bar Overlay - Sheet 1
129. Slide Bar Overlay - Sheet 1
130. Slide Bar Overlay - Sheet 1
131. Slide Bar Overlay - Sheet 1
132. Slide Bar Overlay - Sheet 1
133. Slide Bar Right Upper Main - Sheet 1
134. Slide Bar Right Lower Main - Sheet 1
135. Slide Bar Overlay - Sheet 1
136. Slide Bar Overlay - Sheet 1
137. Slide Bar Overlay - Sheet 1
138. Slide Bar Overlay - Sheet 1
139. Slide Bar Overlay - Sheet 1
140. Slide Bar Overlay - Sheet 1
Bogie
141. Bogie Frame - Sheet 1
142. Bogie Side Overlay - Sheet 1
143. Bogie Side Overlay - Sheet 1
144. Bogie Equalising Bar - Sheet 1
145. Bogie Equalising Bar - Sheet 1
146. Bogie Equalising Bar - Sheet 1
147. Bogie Equalising Bar - Sheet 1
148. Bogie Stretcher
149. Spring Face Plate - Sheet 1
150. Spring Face Plate - Sheet 1
151. Spring Backing Plate - Sheet 1
152. Spring Backing Plate - Sheet 1
153. Spring Backing Plate - Sheet 1
154. Spring Backing Plate - Sheet 1
155. Spring Backing Plate - Sheet 1
156. Spring Backing Plate - Sheet 1
157. Bogie Pivot - Sheet 1
158. Bogie Pivot - Sheet 1
159. Bogie Pivot - Sheet 1
160. Bogie Pivot - Sheet 1
161. Bogie Pivot - Sheet 1
162. Bogie Pivot - Sheet 1
163. Bogie Pivot - Sheet 1
164. Bogie Pivot - Sheet 1
165. Hex Bolt Head - Sheet 1
166. Hex Bolt Head - Sheet 1
167. Bogie Spring Hanger - Sheet 1
168. Bogie Spring Hanger - Sheet 1
169. Bogie Spring Hanger - Sheet 1
170. Bogie Spring Hanger - Sheet 1
Cross Heads
171. Cross Head Rear - Sheet 2
172. Cross Head Rear - Sheet 2
173. Cross Head Overlay - Sheet 2
174. Cross Head Overlay - Sheet 2
175. Cross Head Inner Layers A - Sheet 2
176. Cross Head Inner Layers A - Sheet 2
177. Cross Head Inner Layers A - Sheet 2
178. Cross Head Inner Layers A - Sheet 2
179. Cross Head Inner Layers B - Sheet 2
180. Cross Head Inner Layers B - Sheet 2
181. Cross Head Inner Layers B - Sheet 2
182. Cross Head Inner Layers B - Sheet 2
183. Cross Head Top Overlay - Sheet 2
184. Cross Head Top Overlay - Sheet 2
Valve Gear
185. Valve Rod Left Outer - Sheet 2
186. Valve Rod Left Inner - Sheet 2
187. Valve Rod Right Outer - Sheet 2
188. Valve Rod Right Inner - Sheet 2
189. Outer Rod End Strip - Sheet 2
190. Outer Rod End Strip - Sheet 2
191. Outer Rod End Strip - Sheet 2
192. Outer Rod End Strip - Sheet 2
193. Outer Rod End Spacer - Sheet 2
194. Outer Rod End Spacer - Sheet 2
195. Inner Rod End Strip - Sheet 2
196. Inner Rod End Strip - Sheet 2
197. Inner Rod End Strip - Sheet 2
198. Inner Rod End Strip - Sheet 2
199. Inner Rod End Spacer - Sheet 2
200. Inner Rod End Spacer - Sheet 2
201. Eccentric - Sheet 2
202. Eccentric - Sheet 2
203. Eccentric - Sheet 2
204. Eccentric - Sheet 2
205. Eccentric Bracket - Sheet 2
206. Eccentric Bracket - Sheet 2
207. Eccentric Bracket - Sheet 2
208. Eccentric Bracket - Sheet 2
209. Eccentric Short Bracket - Sheet 2
210. Eccentric Short Bracket - Sheet 2
211. Eccentric Short Bracket - Sheet 2
212. Eccentric Short Bracket - Sheet 2
213. Lifting Arm - Sheet 2
214. Lifting Arm - Sheet 2
215. Lifting Arm - Sheet 2
216. Lifting Arm - Sheet 2
217. Rotation Arm - Sheet 2
218. Rotation Arm - Sheet 2
219. Rotation Arm - Sheet 2
220. Rotation Arm - Sheet 2
221. Rotation Arm End Spacer - Sheet 2
222. Rotation Arm End Spacer - Sheet 2
223. Rotation Arm End Spacer - Sheet 2
224. Rotation Arm End Spacer - Sheet 2
225. Balance Arm - Sheet 2

Page 10 GCR Class 8B
Page 10 GCR Class 8B
226. Valve Rod End - Sheet 2
227. Valve Rod End - Sheet 2
Spares
228. Alternative Cylinder Cover Left
229. Alternative Cylinder Cover Right
Templates
230. Eccentric Template - Sheet 2
231. P4 Width Template - Sheet 3
232. P4 Width Template - Sheet 3
233. EM Width Template - Sheet 3
234. Spare
235. Spare
8C Frames
236. Rear Frame Left - Sheet 2
237. Rear Frame Right - Sheet 2
238. Rear Wheel Spring Mount Locator - Sheet 2
239. Rear Wheel Spring Mount Locator - Sheet 2
NiSi Springs (optional)
240. Spring Layers - Sheet 3
241. Spring Layers - Sheet 3
242. Spring Layers - Sheet 3
243. Spring Layers - Sheet 3
244. Spring - Sheet 3
245. Spring - Sheet 3
246. Spring Support Back - Sheet 3
247. Spring Support Back - Sheet 3
248. Spring Support Back - Sheet 3
249. Spring Support Back - Sheet 3
250. Spring Support Back - Sheet 3
251. Spring Support Back - Sheet 3
252. Spring Front - Sheet 3
253. Spring Front - Sheet 3
Common Parts
1. Drwg. 201 Backhead (1 supplied)
2. Drwg. 203 Footplate Side Cover (2 supplied)
3. Drwg. 205 Oil Box Covers (6 supplied)
4. Drwg. 206 Sand Box Filler (2 supplied)
5. Drwg. 209 Centre Axle Spring (2 supplied)
6. Drwg. 211 Counter Weight (1 supplied)
7. Drwg. 212 Cylinder Front (2 supplied)
8. Drwg. 215 Eccentric Plate (4 supplied)
9. Drwg. 216 Rear Buffer (2 supplied)
10. Drwg. 218 Vacuum Cylinder (1 supplied)
11. Drwg. 219 Bogie Pivot (1 supplied)
12. Drwg. 225 Bogie Axle Box (4 supplied)
13. Drwg. 229 Whistle Markits M4WhistGW2
14. Drwg. 244 Vacuum Pipe Markits (1 supplied) &
Steam Heating Pipe Markits (1 supplied)
15. Drwg. 245 Handrail Knobs
16. Drwg. 246 Reverser
17. Drwg. 249 GCR 3’ 6” Axle Box (2 supplied) - cast
items
18. Drwg. 258 Smoke Box Door (1 supplied)
19. Drwg. 260 Martkits M4HRKWDs (12 Supplied)
20. Drwg. 261 MarkitsRAXFBsq601 axle boxes (4
supplied)
21. Drwg. 262 GC Smoke Box Handle Markits
M4SBDH4
Board 1
22. Brass Wire 0.3 mm Eileen’s BSW031A (25 cm x 2
supplied)
23. Brass Wire 0.45 mm Eileen’s BSW045A (25 cm x
4 supplied)
24. Brass Wire 0.7 mm Eileen’s BSW070A (25 cm x 1
supplied)
25. Nickel Silver Wire 1.6 mm Eileens NSW160A (25
cm supplied)
26. Spring Wire Ernie Ball Gauge 12 (25 cm supplied)
Board 2
27. Reversing Axle Tube 1/16” x1 /32” (1.6 mm x 0.8
mm) Eileen’s BRT0201G (5 cm supplied)
28. Reversing Axle Rod 1/32” (0.8 mm) Eileen’s
BSW080A (5 cm supplied)
29. Valve Rod Tube 3/32” x 1/16” (2.4 mm x 1.6 mm)
Eileen’s BRT0302G 300 mm (10 cm supplied)
30. Cab Roof Front & Rear Brace (‘L’) Eileen’s Brass L
Section 1/32" x 1/32" x 12" (KS A1) (15 cm
supplied)
31. Cab Roof Centre Brace (‘T’) Brass T Section 1/32"
x 1/32" x 12" (KS T1) (5 cm supplied)
32. Brass Round Tube 0.8 mm x 0.4 x 305 mm (MT2)
Eileen’s BRT0804D (smoke box hinges) (5 cm
supplied)
Sundries (Drwg. 266)
33. Dome Head Rivet 08MBV07B (2 supplied)
34. 10 BA Bolts (4 supplied)
35. 10 BA Nuts (4 supplied)
36. 14 BA Bolts (4 supplied)
37. Washout Plugs Eileens LF4WP01 (9 supplied)
Alternative 3D printed components if required
1. Drwg. 224 Spring Hanger Blocks (2 supplied) -
may be used as an alternative to the etch version
2. Drwg. 247 B1C4 Brakes (4 supplied) - may be
used as an alternative to the etch version or top
of the etch base for additional strength - allows
brakes to sit very close to wheels
3. Drwg. 249 GCR 3' 6" Axle Box (2 supplied) -
replaces casting if not available
4. Drwg. 257 C4 Rear Brakes (2 supplied) - may be
used as an alternative to the etch version or top
of the etch base for additional strength - allows
brakes to sit very close to wheels

Page 11 GCR Class 8B
Page 11 GCR Class 8B
Locomotive Body
0.012’ 0.3 mm Brass
Boiler
1. Boiler - Sheet 4
2. Boiler Front - Sheet 4
3. Boiler Rear - Sheet 4
4. Smoke Box Frame +EM - Sheet 6
5. Smoke Box +EM - Sheet 6
6. Smoke Box Wrapper - Sheet 5
7. Smoke Box Wrapper Riveted - Sheet 5
8. Smoke Box Step - Sheet 4
Footplate
9. Footplate Left +EM - Sheet 6
10. Footplate Right +EM - Sheet 6
11. Footplate Rear +EM - Sheet 6
12. Footplate Front - Sheet 6
13. Footplate Hinge - Sheet 6
14. Footplate Hinge - Sheet 6
15. Lamp Bracket Footplate - Sheet 6
16. Lamp Bracket Footplate - Sheet 6
17. Lamp Bracket Footplate - Sheet 6
18. Valence Left - Sheet 4
19. Valence Right - Sheet 4
20. Splasher Side Left Front - Sheet 4
21. Splasher Side Left Centre - Sheet 4
22. Splasher Side Right Front - Sheet 4
23. Splasher Side Right Centre - Sheet 4
24. Not Defined
25. Not Defined
26. Splasher Top Left Front +EM - Sheet 6
27. Splasher Top Left Centre +EM - Sheet 6
28. Splasher Top Right Front +EM - Sheet 6
29. Splasher Top Right Centre +EM - Sheet 6
30. Footplate Support Top+EM - Sheet 6
31. Footplate Support Top+EM - Sheet 6
32. Footplate Support Top+EM - Sheet 6
33. Footplate Support Top+EM - Sheet 6
34. Footplate Support Bracket+EM - Sheet 6
35. Footplate Support Bracket+EM - Sheet 6
36. Footplate Support Bracket+EM - Sheet 6
37. Footplate Support Bracket+EM - Sheet 6
38. Oil Filler Caps - Sheet 4
39. Oil Filler Caps - Sheet 4
40. Oil Filler Caps - Sheet 4
41. Oil Filler Caps - Sheet 4
42. Oil Filler Caps - Sheet 4
43. Oil Filler Caps - Sheet 4
Fire Box
44. Fire Box - Sheet 4
45. Fire Box Cab - Sheet 4
46. Inspection Cover - Sheet 5
47. Inspection Cover - Sheet 5
48. Inspection Cover - Sheet 5
49. Inspection Cover - Sheet 5
50. Inspection Cover - Sheet 5
51. Fire Box Brace - Sheet 5
52. Fire Box Brace - Sheet 5
53. Fire Box Brace - Sheet 5
54. Fire Box Brace - Sheet 5
Cab
55. Cab Side Left - Sheet 5
56. Spare
57. Cab Side Right - Sheet 5
58. Spare
59. Not Defined
60. Not Defined
61. Edging Left Strip - Sheet 5
62. Edging Right Strip - Sheet 5
63. Cab Front - Sheet 5
64. Cab Window Overlay - Sheet 5
65. Cab Window Overlay - Sheet 5
66. Cab Window Overlay - Sheet 5
67. Cab Window Overlay - Sheet 5
68. Roof - Sheet 5
69. Reversing Arm Cab End - Sheet 4
70. Reversing Arm Chassis End - Sheet 4
71. Reversing Arm Cab Arm - Sheet 4
72. Reversing Arm Actuator - Sheet 4
73. Reversing Arm Actuator - Sheet 4
74. Reversing Lever Front Actuator - Sheet 4
Cupboards
75. Cupboard Left - Sheet 5
76. Cupboard Right - Sheet 5
77. Door Hinge - Sheet 5
78. Door Hinge - Sheet 5
79. Door Hinge - Sheet 5
80. Door Hinge - Sheet 5
81. Footboard Left - Sheet 5
82. Footboard Right - Sheet 5
83. Shelf Left - Sheet 5
84. Shelf Right - Sheet 5
85. Cab Handle - Sheet 5
86. Cab Handle - Sheet 5
87. Cab Handle - Sheet 5
88. Cab Handle - Sheet 5
89. Cab Floor - Sheet 6
Steps
90. Centre Step Plate Left - Sheet 4
91. Centre Step Left Upper - Sheet 4
92. Centre Step Left Lower - Sheet 4
93. Centre Step Plate Right - Sheet 4
94. Centre Step Right Upper - Sheet 4
95. Centre Step Right Lower - Sheet 4
96. Rear Step Plate Left - Sheet 4
97. Rear Step Left Upper - Sheet 4
98. Rear Step Left Lower - Sheet 4
99. Rear Step Stabiliser - Sheet 4
100. Rear Step Plate Right - Sheet 4
101. Rear Step Right Upper - Sheet 4
102. Rear Step Right Lower - Sheet 4
103. Rear Step Stabiliser - Sheet 4
Cylinders
104. Cylinder Cover Left - Sheet 4

Page 12 GCR Class 8B
Page 12 GCR Class 8B
105. Cylinder Cover Right - Sheet 4
Springs
106. Axle Box Spring Mount - Sheet 4
107. Axle Box Spring Mount - Sheet 4
108. Axle Box Spring Mount - Sheet 4
109. Axle Box Spring Mount - Sheet 4
110. Rear Wheel Spring Mount - Sheet 5
111. Rear Wheel Spring Mount - Sheet 5
Wheels
112. Centre Wheel Weights - Sheet 5
113. Centre Wheel Weights - Sheet 5
114. Wheel Weights - Sheet 5
115. Wheel Weights - Sheet 5
116. Not Defined
117. Not Defined
Bits and Pieces
118. Lamp Bracket Top - Sheet 4
119. Smoke Box Handle - Sheet 4
120. Smoke Box Handle - Sheet 4
121. Regulator Lever - Sheet 4
122. Regulator Plate - Sheet 4
123. Regulator Plate - Sheet 4
124. Footplate Connection - Sheet 4
125. Smoke Box Door Hinge - Sheet 4
126. Cab Roof Blanking Plate - Sheet 5
127. Ramsbottom Actuators - Sheet 4
128. Ramsbottom Actuators - Sheet 4
129. Ramsbottom Side Cover - Sheet 5
130. Rear Wheel Spring Mount Locator - Sheet 5
131. Rear Wheel Spring Mount Locator - Sheet 5
Assembly Aids
132. Valence Spacing Aids +EM - Sheet 5
133. Valence Spacing Aids +EM - Sheet 5
134. Valence Spacing Aids +EM - Sheet 5
135. Valence Spacing Aids +EM - Sheet 5
136. Footplate Assembly Aid - Sheet 4
137. Cab Assembly Aid - Sheet 5
138. Cab Assembly Aid - Sheet 5
139. Fire Box Support Aid - Sheet 5
140. Fire Box Support Aid - Sheet 5
141. Belpaire Filing Aid - Sheet 5
GCR Class 8B
1. Drwg. 254 Dome Original (1 supplied)
2. Drwg. 251 Chimney Original (1 supplied)
3. Drwg. 239 Ramsbottom 4-column Safety Valve
4M778 Alan Gibson
LNER C4
4. Drwg. 252 Chimney Flowerpot (1 supplied) or
Drwg. 253 Chimney GCR Pseudo (1 supplied)
5. Drwg. 255 Dome Reduced (1 supplied)
6. Drwg. 228 Snifter (1 supplied)
7. Ross Pop Safety Valves Markits MASftyV7 £3.26
(2 supplied)
Additional Parts Required - not part of the kit
Wheels, motors and gears are a personal choice - these were
the ones used by the designer
1. Wheels Gibson G4880B 6’ 8” Dia. Alan Gibson
2. Crank Pins 4M42B Alan Gibson
3. Bogie Wheels G4842 3’ 6” Dia. Alan Gibson
4. Rear Wheel G4851 4’ 3”12 Spoke Alan Gibson
5. High Level Gear Box SlimLiner 40:1 2mm shaft
6. Mashima Motor 2mm shaft
7. Buffers AG 4M4901 £5.00 set of four or 4M4909
or Markits LNER Stepped
8. Markits Screw Couplings MCOUP/S
Recommended Tool
If 14 BA bolts are used to fix the cosmetic springs
CSTB141 Carbon Steel Taper Tap 14BA Eileen’s £14.40
If the eccentrics are fitted you will need a 16 BA tap
Carbon Steel Taper Tap 16BA CSTB161 £20.00

Page 13 GCR Class 8B
Page 13 GCR Class 8B
Main Frame Preparation
Note
You may wish to leave the main frames in the fret while
preparing them. I have found this a lot easier and only remove
the frames from the fret when I am ready to join the frames
together
Note
There seems to be a little photographic evidence that when first
built there were no visible, proud rivets on the frames under the
smoke box. Check photographs if this is of concern.
Before pushing out the rivets around the top of the frame under
the smoke box and those on the fire box sides you may wish to
test the pressure needed using the spare half etched holes which
are on Sheet 1.
Note that the frames on this locomotive have a distinct bend
inwards under the smoke box and this is modelled in P4 only.
Since the frames need to be closer together for EM gauge, they
must remain straight and therefore a short piece of 0.45 mm
wire should be soldered into the bend slot to strengthen the
frame at this point.
Note - small radius running
On the inside of the frames above the position of the bogie are
half etched lines. These indicate the cutting needed to allow the
bogie to move much more than would be prototype practice. If
your curves are less than 1200 mm radius then these must be cut
out. It is better to do this when the frames are assembled and
have some rigidity.
Push out the rivets under the smoke box, be careful with the top
row, they are close to the edge. Use the “Play Pen” area on Sheet
2 to practice.
Drill out the frame stiffener locating holes to 0.3 mm in Frame
Left (1) and Frame Right (2) - see picture right.
Measure the short handrail tails which will be used for the
springs (they will be about 0.7 mm diameter) and then drill out
the 6 spring mount positions shown (and marked as 0.65 mm in
the picture on the right) if you require active springing. Push the
handrails supplied into place on the inside of the frames, using a
length of 0.3 mm steel wire through the holes to align them and
solder them into place. Carefully file off the protruding tails on
the outside of the frames.
Drill out the holes for the cosmetic, removable springs, 6 each
side, which are located either side of the horn block spacing for
the front and rear axles only, to 0.80 mm to clear 16 BA c/s bolts
(not supplied) or 1.05 mm to clear 14 BA c/s bolts (supplied).
Carefully countersink the outer face very slightly for the fixing
bolts.
Drill out the brake shaft holes, 3 each side, to 0.7 mm - see
picture right.
Drill out the reversing arm holes to 0.8 mm - see picture right.
1. Frame Layout
9. Cab Base Support
Wheel Height Centres
Spring Mounts
Cosmetic Removable Springs
12,13,14,15. Rear Frame Spacer
16-18. Centre Frame Spacer
Reversing Arm
19-21. Valve Guide
Fire Box
Brake Shaft
Brake Shaft
Spring Mounts
38. Footplate Fixing Bracket
Cut Out Guides for small radii running
0.33 mm
0.33 mm
0.33 mm
0.7 mm
0.5 mm 0.5 mm
0.5 mm
0.5 mm
0.7 mm
0.65 mm
0.65 mm
0.65 mm
0.65 mm
24,25. Buffer Supports
11. Smoke Box Base
48. Bogie Mount
26,27. Sand Boxes
0.65 mm
0.65 mm
Spring Mounts 10. Fire Box Base
0.8 mm
Rear Wheel Centre
Rear Wheel Brake Shaft
Rear Wheel Spring Mount
Locators (238,239)

Page 14 GCR Class 8B
Page 14 GCR Class 8B
Remove Rear Wheel Spring Mount Locators (238,239) from the
fret, fold with the etch on the outside and locate in place on the
insides of the frames.
Fire Box
Note
The firebox is inset from the sides of the frames as on the
prototype. This is located into the inside of the frame using
locating holes and brass wire.
Locate Fire Box Left (47), Fire Box Right (46) and Fire Box Brace
(42) on the fret, drill the 0.3 mm holes in the fixing tabs, press
out the rivets from the back and then remove from the fret. Bend
to shape and and solder into place inside the main frames using
0.3 mm wire to locate them. Fit Fire Box Brace (44) at the front of
the fire box at the correct angle to match the front slope.
Scale frame cross members
Locate parts Rear Frame Spacer Stiffener Left (14) and Rear
Frame Spacer Stiffener Right (15). Drill out the very small
locating holes to 0.3 mm. Remove these parts from the fret and
with the aid of some 0.3 mm brass wire locate and solder into
place on the inside of both frames.
Locate parts Centre Frame Spacer Stiffener Left (17) and Centre
Frame Spacer Stiffener Right (18). Drill out the very small
locating holes to 0.3 mm. Remove these parts from the fret and
with the aid of some 0.3 mm brass wire locate and solder into
place on the inside of both frames.
Locate parts Valve Guide Support Spacer Stiffener Left (20) and
Valve Guide Support Spacer Stiffener Right (21). Drill out the
very small locating holes to 0.3 mm and the larger holes to 0.7
mm. Remove these parts from the fret and with the aid of some
0.3 mm brass wire and some 0.7 mm brass wire for the larger,
lower holes locate and solder into place on the inside of both
frames.
Generic frame cross members
On Sheet 3 there are 2 generic cross members for either P4 or
EM. You may wish to use these in place of the scale cross
members. They are labelled as P4 or EM. Choose the locations
you prefer to use bearing in mind possible locations for pickup
wiring and make a light pencil mark. Note that you will probably
not need more than one of these and that it must not interfere
with the action of the Stephenson’s Valve Gear if that is fitted.
2.Fire Box
Left side shown with front
of chassis on the left of
picture
3. Main Frame Spacers
Half view - left side only shown
16-18. Centre Frame Spacer
12-15. Rear Frame Spacer
10. Fire Box Support
9. Cab Base Support
Half view - left side only shown
19-21. Valve Guide Spacer
11. Smoke Box Base
38. Footplate Fixing Bracket
48. Bogie Mount
Optional
Optional
Remove for EM and ‘00’

Page 15 GCR Class 8B
Page 15 GCR Class 8B
Connecting the frames together
Note P4 Only
The frames have a half etch bend close to the front. Now is the time to very carefully bend this inwards (it is only 2 degrees), Use
a pair of flat nosed pliers to hold the frames so that the elongated hole for the cylinder spacers is covered and will be held flat.
The smoke box base is etched to allow for this bend.
Note
The etching process is not always accurate so it may be wise to lightly file the cusp from the spacers where they meet the frames
before fitting, it is usually the tiniest bit that is needed. In an ideal world the width over the frames should be 16.10 mm for P4
and 14.70 for EM. Use +/- 0.1 mm as a general guide although it won’t hurt too much if a little more under sized.
Use the P4 Width Templates (231-235) to check if you do not have a micrometer.
Only solder the next parts solidly into place after they have all been fitted and checked. Even with very light tacking the frames
will be solid enough work on.
Remove parts Cab Base Support (9 or 9EM),Fire Box Base (10 or 10EM),Smoke Box Base (11 or 11EM) and Bogie Mount (48
or 48EM) from the fret, check the tabs are clean, bend to shape and one by one do a test fit into between the two frames.
Solder each of these parts into place very lightly starting with Cab Base Support (9 or 9EM). Ensure it is fitted the correct way,
the larger holes are on the underneath and are there to fit the cab and upper body to the chassis.
Fire Box Base (10 or 10EM) should be fitted in place and initially soldered on one side only.
Remove parts Valve Guide Support Spacer (19 or 19EM), Centre Frame Spacer (16 or 16EM),Rear Frame Spacer (12 or 12EM)
and Rear Frame Spacer Brace (13 or 13EM). Solder these in place checking the width of the frames carefully after each one
(16.20 mm for P4 and 14.80 for EM).
Once these are fitted and you are certain the frame is within the specified width then the Firebox Base (10 or 10EM) can be
soldered up on both sides.
Ensure that the large holes in Valve Guide Support Spacer (19 or 19EM) are clear so that the 2.4 mm tubing can fit in them. The
Smoke Box Base (11 or 11EM), Valve Guide Support Spacer (19 or 19EM) and Bogie Mount (51 or 51EM) can now be added to
the frames.
Check the chassis is still square after soldering each part lightly into place.
Slide Bar Stiffeners
Locate parts Slide Bar Support Left (22),Slide Bar Support Right (23). Drill out the very small locating holes to 0.3 mm and the
larger holes to 0.7 mm - the larger hole is also the brake pivot axle. Remove these parts from the fret and with the aid of the
locating wires solder to the outside of both frames noting that the stiffener part is to the rear of the frames.
Brake Frame Mounts
Remove parts Brake Frame Mounts (69-74) from the fret and
solder to the inside of the frames using 0.7 mm brass wire to
locate. When trimming this 0.7 mm wire do not use a pair of
cutters between the frames since this will seriously distort
them. Use a disc cutter or a triangular file to grind away a cut
in the centre.
Now add the brake spacers - these are used to ensure the
brake shoes are at the correct distance from the frames. They
are made from brass tubing which is 1/16” x 1/32” (1.6 mm x
0.8 mm ) and are 1 mm in length. Solder into place. Later, the
brake shoe assembly will simply clip over this.
Sand Boxes
Remove parts Sandbox Left (26) and Sandbox Right (27) from
the fret and fold to shape - locate the tabs just to the rear of
the smoke box and solder lightly to the main frames.
4. Slide Bar Supports and Sand Box
Slide Bar Support Left (22)
Sandbox Left (26)

Page 16 GCR Class 8B
Page 16 GCR Class 8B
Caveat
It will look nice if you fit the buffers next but it will be wrong
because it may inhibit the ease with which the parts of the
cylinders can be fitted such as when holes need to be reamed
out slightly etc
Cylinders
Note
The Cylinder Spacers (7,8) have a number of guide holes in
them. The inner pair are for the valve guide rod tubing. Just
outside of these are two 0.3 mm holes which can be used as
guides for locating the spacers accurately across the frames
(use the inner pair of these for EM and the outer for P4). There
are also two 0.45 mm holes each end which are used to locate
the Cylinder Heads (52-55). The two rectangular holes locate
the slide bars.
You may wish to consider using the Markits Double Slide bar
and Crosshead (M4CRHDSns) instead of the supplied cross head.
Drill out the 0.3 mm and 0.45 mm holes. Drill the larger, central, holes for the valve rod to 1.6 mm minimum, for an easier fit of
the working valve gear this should be 1.8 mm. Drill or ream the large outer holes to 2.4 mm if you intend to use a tube down the
centre of the cylinders or 2.1 mm for the Markits crosshead. You may choose to drill out the valve rod holes to 2.4 mm as well
and fit 2.4 mm tubing.
Remove Cylinder Spacers (7,8) from the fret and fix into the correct position using 0.3 mm brass wire as a guide, the outer holes
are for P4 and the inner holes are for EM. The cylinder tubes fit in the central end holes with the two rectangular holes used to
locate the slide bars.
Drilling Note
When drilling out the cylinder heads it may help to stabilise them if you solder temporarily a length of 0.9 mm brass wire across
one side since drilling them to 2.4 mm will put quite a strain on the tag holding them into the etch. An easier way to drill out
these 2.4 mm holes may be to temporarily solder the part to a bit of scrap and then drill, then un-soldering and fitting as normal.
Drill the two small holes in Cylinder Heads (49-52) to 0.45 mm. Drill the large centre hole to 2.4 mm or for the Markits crosshead
2.1 mm. Remove Cylinder Heads (49-52) from the fret and solder securely in place on the front of the front cylinder support
and the rear of the rear cylinder support using 0.45 mm brass wire to align them.
For the supplied crossheads, fit a length of 3/32” x 1/16” brass tube (2.4 mm x 1.6 mm) so that it is just proud at the front and is
2 mm proud at the rear, 14 mm in total. At the front this fits into the Drwg. 212 Cylinder Front. The front cylinder cover will have
a 1.6 mm tail rod (or the cut down version later) which will help to locate it into the cylinder block.
Slot short lengths of 1.6 mm rod through the inside holes of the Cylinder Spacers (7,8) so that it also runs through the Valve
Guide Spacer (19). Then slot a short length of 2.4 mm tube into the Valve Guide Spacer (19) so that at the rear there is 2 mm
showing and about 4 mm at the front. This will align the rods to the valve chest if fitted along with the Stephenson’s Valve Gear
and simulates the bearing and oiler on the full size locomotive. Solder this in place and remove the 1.6 mm rod.
Slide Bars
Note
Alternatively, the slide bars may be made up from 1 mm x 1 mm nickel silver bar, soldering one part on the top of the other and
filing to shape or using 2 mm x 1 mm bar and again filing to shape.
Parts 125-140 form Qty 4 identical slide bars. These are built up in four layers and soldered together with the aid of 0.3 mm brass
wires to locate and secure the individual layers. These are then filed to the correct shape.
Note that the short layer at the top is positioned the correct way around!
Remove Slide Bar Left Upper Main (125) (long), Slide Bar Overlay (127) (long with half etch section), Slide Bar Overlay (128)
(medium) and Slide Bar Overlay (129) (short) from the etch. Locate using 0.3 mm brass rod and solder up well using high
melting point solder with Nealetin as the flux - or similar.
5.Cylinders and Slide Bars
Cylinder Spacers (7,8)
Cylinder Heads (49-52)
Slide Bar Assembly

Page 17 GCR Class 8B
Page 17 GCR Class 8B
Complete the other slide bar parts as above and file to correct profile. They should be 1 mm wide and at the deepest point 1.2
mm.
Insert a pair of slide bars into each side of the frames and check they locate correctly and not too tightly into the cylinder head
rectangular slots with a small protrusion at the front. Ensure that they fit between the Slide Bar Supports (22,23).
Do not solder up at this stage, first the crossheads must be assembled and then tested for a smooth sliding fit! It is likely that a
small adjustment with a file will be needed to the slide bar supports to achieve the desired 4.66 mm spacing all along the slide
bars.
Crossheads
Note
An alternative to the crosshead assembly provided is the Markits Double Slide bar and Crosshead (M4CRHDSns). However, while
this looks very nice it is not deep enough between the slide bars, which means that the locating holes in the cylinder heads must
be adjusted very slightly inwards. The upper and lower slots of the cross heads must be slightly widened to suit the slide bars.
The Crossheads provided are built up in layers. There are two outer layers (one of them partly half etched to show the profile),
two inner layers one of which is half etched and two inside layers which are shaped to allow the Connecting Rods to partially
rotate. All of these should be used unless you are confident of great accuracy in which case the half etch layer may be left out.
Remove the two sets of Cross Head parts (171-184) from the fret and align each set locating them in place with a steel pin or
something else suitable through the centre into several layers of balsa or other hardwood. If using hardwood such as Ramin
then drill a hole as deep as possible to suit the steel pin. In preference use a higher melting point solder than normal and use
lots of heat. This will allow the parts to be re-aligned should they
move.
Solder these layers together. Do not pick this up too soon, it will
have got very hot!
Trim and file to finish, the top and bottom edges should be filed
down to less than the depth of the slide bars. Do a test fit to
make sure these slide easily.
In the end of the cross heads drill a small hole 1.6 mm to accept
the cross head rod which is 1/16” brass rod of length 25 mm.
Solder this in place ensuring that the cross head is securely
clamped. Do a test fit to ensure it slides easily into the cylinder
tubing.
Check the measurements for the sliding faces on the crossheads
- this should be 4.67 mm for the supplied version (equivalent to
1’ 2”). For the corresponding slide bars the distance between
them is 4.8 mm. Ensure this is the case, filing and trimming as
needed. This will make a nice close fit without being too tight - a
little oil helps here.
7. Cross Heads
Cross Head Rear (171)
Cross Head Overlay (173
Cross Head Top Overlay (183)
Cross Head Inner Layers A
Cross Head Inner Layers B
6. Slide Bar Measurements

Page 18 GCR Class 8B
Page 18 GCR Class 8B
File down the top and bottom carefully so that they do not hit
the Slide Bar Supports (22,23) and can move freely along the
length of the slide bars.
Coupling Rods
Note
The coupling rods are a mirror pair - so take care that all the oil
boxes end up at the top!
A range of extra parts are provided either full depth or half
etched to be attached to the bosses on the coupling rods either to
the front or the rear. These will allow you to choose how far to
off-set the wheels from the coupling rods. The boss at the rear of
the coupling rods is optional.
There is very little space behind the connecting rod in P4 so if
using the Alan Gibson crank pins and locknuts then the leading
hole in the Coupling Rods Left and Right Front (105,111) should
be opened up to 1.8 mm so that the locknut can fit into into it in
reverse. In Extremis is it just possible to open out the hole in
either top boss or the overlay to 2.5 mm so that the whole nut is
countersunk.
A better solution may be to use the crank pins designed by Tim
Venton (see Scalefour Society Forum). These are threaded and
the front one is countersunk into the coupling rods hole.
Drill 1.5 mm to 1.6 mm through all the other crank pin holes to
suit your crank pin bearings. The front crank pin is rather shorter
than on the other axles if the crank pin nut is reversed.
Drill out the coupling rods to suit your choice of crank pins.
Remove Coupling Rod Left (105),Coupling Rod Left Overlay
(106) from the fret.
Remove Coupling Rod Bosses (107-110) from the fret, select and
solder in place to inside and/or outside of main coupling rods.
Repeat for the right side coupling rods using parts (111-116).
Connecting Rods
Note
The Connecting Rods are a mirror pair.
Remove parts Connecting Rod Left (117),Connecting Rod Left
Overlay (118),Connecting Rod End Overlay (121) (square),
Connecting Rod End Overlay (122) (round) from the fret and
solder together.
The hole which fits over the centre axle crank pin should be
opened out to (1.5 mm to 1.6 mm) to suit your crank pin bearing.
The small end of the Connecting Rod should fit inside the
Crosshead Assembly and is secured with a 0.5 mm rivet (lightly
hammer in place or soldered on the rear according to
preference). A short piece of 0.45 mm brass wire will suit as well.
Leave the front slightly proud to represent the fixing bolt.
Repeat for the other connecting rod.
Buffers Beams - rear
Note
9. Connecting Rods
Connecting Rod Left Overlay (118)
Connecting Rod Left (117
Connecting Rod End Overlay (121)
Connecting Rod End
Overlay (122)
8. Coupling Rods
Coupling Rod Left Overlay (106)
Coupling Rod Bosses
Coupling Rod Left (105)

Page 19 GCR Class 8B
Page 19 GCR Class 8B
There is no reason why the buffer layers should not be made part
of the foot plate and soldered to the ends of the footplate using
the rear and front foot plates and the valences as a guide, which
may make fitting body and chassis together a little easier. If this
is done the tabs on the ends of the frames should be carefully
filed flat since they will no longer have a purpose.
The rear buffer has two layers. Drill holes 0.45 mm in Rear Buffer
Beam (5), Rear Buffer Beam Overlay (6) and Rear Buffer Housing
Plates (38,39). Drill large holes in Rear Buffer Beam Overlay (6)
and Rear Buffer Housing Plates (38,39) to 2.0 mm which will
locate the un-sprung rear buffers.
The Rear Buffer Beam (5) has four slots for the frames, the outer
pair of each pair is for P4 and the inner pair is for EM. The outer
pairs are for the secondary (external) frame.
Remove Rear Buffer Beam (5) from the fret and solder over the
end of the frames ensuring it is the right way up, the two slots
are nearer the bottom.
Remove Rear Buffer Beam Overlay (4) from the fret and solder
half etched Rear Buffer Beam Overlay (6) in place again ensuring
it is the right way up. The holes and slot are nearer the top.
Remove Rear Buffer Housing Plates (36,37) from the fret and
solder into place. Ream out the central holes and fit the Cast or
turned Rear Buffers.
Remove Rear Buffer Beam Draw Bar Plate (41) from the fret and
solder it in place to match the draw plate slot.
Fit Drwg. 216 Rear Buffers in place and solder.
Secondary Frame
Push out the rivets if required in Rear Frames (236,237) and
remove them from the fret.
Bend so that the half etch is on the inside and insert into the
sides of the frame and one of the outer pair of slots in the rear
buffer depending on whether you are modelling in P4 (outer) or
EM (inner).
Buffers Beams - front
Note
The Buffer Mounts (32,33) are optional. When first built they
were not fitted but were added later. The rear part of the Gibson
buffers (small circle with a hole in the centre) may be mounted
behind the buffer beam, in which case a small notch needs to be
filed to accommodate it. The four small holes in the corner may
be used to locate the buffer mounts and again optionally, the
Gibson buffers may be drilled out in each corner to 0.45 mm so
that the fixing bolts may be simulated.
The front buffer has two layers. To simulate the bolts that hold
the buffers to the buffer beam drill the locating holes in Front
Buffer Beam (3), Front Buffer Beam Overlay (4) and Buffer
Mounts (34,35) to 0.45 mm.
Remove Front Buffer Beam (3),Front Buffer Beam Overlay (4),
Buffer Support Left (24),Buffer Support Right (25) and Buffer
Mounts (32,33) from the etch.
11. Rear Buffer B (from front)
Slots for frame tabs (P4 outer)
Slots for frame tabs (EM inner)
Front Buffer Beam (3)
Front Buffer Beam Overlay (4)
Frames - shown in
P4 mode - curved
inwards
12. Front Buffer A
Front Buffer Beam
Draw Bar Plates
(39,40)
Buffer Mounts (32,33)
10. Rear Buffer A (from rear)
Rear Buffer Beam (5)
Rear Buffer Beam
Overlay (4)
Rear Buffer Housing Plates (36,37)
Rear Buffer Beam Draw Bar Plate (41)
Drwg. 216 Rear Buffers

Page 20 GCR Class 8B
Page 20 GCR Class 8B
Solder the buffers to Buffer Mounts (32,33) then drill through
0.45 mm from the rear for the corner fixing bolts.
Remove Foot Plate Fixing Bracket (38) from the fret and fit
between the frames. This part should have the TABS removed
and then it can sit either above or below the TABS from the
Buffer Supports (24,25). Fitting it below will allow a deeper 10 BA
fitting to be used under the footplate.
Note
Before fitting the buffer beams permanently it is worth checking
that the valve rod guides and cylinder guides are clear and
accurately set. It is difficult to check these with the buffer beams
in place.
Fix the Front Buffer Beam in place to the frames at the same
time as the Buffer Supports noting that the buffer beam slot is
closer to the top. Check the front buffer beam is square since for
P4 the frames have a distinct bend at 4’ from the front buffer
and if the bend if different at each side the buffer will not be
central. P4 and EM modellers use the same front slot for the
frames.
Ensure the Front Buffer Beam (3) is flat and then using 0.3 mm
brass wire and a couple of clamps locate the buffers, Front Buffer
Beam Overlay (4) and Buffer Mounts (34,35) and solder carefully
into place. Trim off the 0.3 mm wire to represent the bolt heads
on the buffers.
Remove Front Buffer Beam Draw Bar Plates (39,40) from the
fret, clean up where needed and solder into place.
Remove Couplers (34,35) from the fret and solder into the front
buffer beam.
Brake Cylinder Support
Remove parts Brake Cylinder Supports (28,29) from the fret, drill
the smaller hole to 0.45 mm (this takes the safety chain link to
the tender) and drill the larger hole to 1.0 mm for the actuating
axle for the brakes.
Solder into place under Cab Base Support (3) and check they are
square to this base.
Fit the cast/turned/printed Drwg. 218 Vacuum Cylinder after all
soldering is completed.
Stephenson’s Valve Gear
Note
The Stephenson’s Valve gear consists of mirror images of parts on
the centre axle. They can be configured to work by locking them
to the centre axle or may be left to rotate freely.
Make sure that the correct parts are on the outside or the
eccentrics may become twisted. Also note that parts for the
eccentric have a ‘tab’ on them and additional fixing holes to help
in getting them soldered up. After soldering these and before
fitting into the main motion these tabs are filed to the correct
shape. High melting point solder is recommended. Brass wire 0.3
mm is used to locate the parts accurately.
For parts 185-200 drill out all the locating holes to 0.3 mm.
14. Brake Cylinder Supports
Brake Cylinder Supports (28,29)
Left frame only shown, Cab
Base and Rear Buffer
15. Valve Gear Outer Rod
Valve Rod Right Outer (187)
Outer Rod End Strips (189,190)
Outer Rod Spacer (193)
16. Valve Gear Inner Rod
Valve Rod Right Inner (188)
Inner Rod Spacer (199)
Inner Rod End Strips (195,196)
Buffer Supports (24,25)
Foot Plate Fixing
Bracket (38)
13. Front Buffer B