QSI QS-2plus! User manual

QS-2plus!
Sound and Control
for 3Rail
Reference Manual

Table of Contents
CONGRATULATIONS!................................................................................6
1. SETTING UP .............................................................................................7
EQUIPMENT LIST...........................................................................................7
HOW TO WIRE YOUR TRANSFORMER .............................................................8
MORE: QSI PowerTrak....................................................................................9
CONNECTING A LIONEL BELL BUTTON ........................................................10
MORE: Lionel Horn and Bell Buttons............................................................11
MORE: QSI SideKick II.................................................................................11
THE BACK-UP BATTERY...............................................................................12
2. STARTING UP ........................................................................................13
TRANSFORMER IDENTIFICATION...................................................................13
CHANGING ENGINE DIRECTION....................................................................14
The Horn Button Has Many Uses .......................................................................14
MORE: Multiple-Heading..............................................................................15
3. SOUND.....................................................................................................16
HORN OR WHISTLE......................................................................................16
BELL ..........................................................................................................17
COUPLER ....................................................................................................18
MORE: QSI Coil Coupler...............................................................................20
PFA (PASSENGER/FREIGHT ANNOUNCEMENT)..............................................21
MORE: QS-2+ Sounds...................................................................................22
4. RESET FEATURES.................................................................................26
WHAT IS RESET.........................................................................................26
Special QS-2+ Commands Are Available In RESET............................................26
HOW TO SELECT THE RESET FEATURE YOU WANT......................................27
How to Locate RESET Positions.........................................................................28
Step by Step Description of Moving through RESET Features.............................29
MORE: Selecting with the Direction Button on Your Transformer..................30
HOW TO OPERATE RESET FEATURE CHOICES ..............................................30
MORE: Transformer Horn Buttons.................................................................30
MORE: How to Find out which RESET Feature Choice is Set........................31
5. ASSIGNING AND USING ID NUMBERS..............................................32
RUNNING 1 TO 10 ENGINES WITH TEMPORARY ID NUMBERS.........................32
MORE: Making up and Breaking up Trains....................................................33
ENGINE PLUS: AN EASY WAY TO MAKE UP AND BREAK UP TRAINS ...................34
USING ROAD AND ENGINE ID NUMBERS ON LARGE LAYOUTS........................36
USING ROAD, ENGINE AND TEMPORARY ID NUMBERS TOGETHER .....................38

6. RESET FEATURE GUIDE..................................................................... 40
#0: TEMPORARY/ ROAD ID SELECT, ALL SELECT ........................................ 42
MORE: How to Run Multiple-Headed Trains.................................................44
#1: ENGINE SELECT.................................................................................... 45
#2: TEMPORARY ID SET.............................................................................. 47
#3: TEMPORARY ID CLEAR......................................................................... 48
#4: SLAVE ENGINE...................................................................................... 49
#5: START-UP DIRECTION ........................................................................... 51
#6: DIESEL MOTOR/STEAM CHUFF/ELECTRIC FAN/ TURBINE VOLUME......... 53
#8: ENGINE LIGHTS .................................................................................... 54
#10: COUPLER ENABLE.............................................................................. 55
What Is a Trailing Coupler and How Is It Used?................................................56
#11: AUTOMATIC OPERATION .................................................................... 58
#15: ROAD ID SET...................................................................................... 60
#16: ENGINE ID SET................................................................................... 62
#17: ROAD AND ENGINE ID CLEAR............................................................. 63
#18: OPERATIONAL CLEAR.......................................................................... 64
#19: TRANSFORMER TYPE........................................................................... 65
More: About Auto Select................................................................................66
#20: SYSTEM TYPE..................................................................................... 67
#23: DIESEL/ELECTRIC/GAS TURBINE CAB CHATTER OR STEAM NEUTRAL
SOUNDS ..................................................................................................... 68
#25: DIESEL HORN OR STEAM WHISTLE IN NEUTRAL ................................... 69
#27: STEAM CHUFF THRESHOLD AND CHUFF RATE OR DIESEL MOTOR
THRESHOLD ............................................................................................... 70
MORE: QS-2+ Eliminates Cams ....................................................................70
#28: PASSENGER OR FREIGHT ANNOUNCEMENT (PFA) OR QSI STATION
MASTER (QSM) ENABLE ............................................................................ 76
#30: WARNING LIGHT OPTIONS................................................................... 78
#32: FEEDBACK IN RESET.......................................................................... 79
#35: FACTORY TEST................................................................................... 80
#37: "I THINK I CAN" FOR SMALL STEAM ENGINES....................................... 81
#40: LOCK-OUT ENABLE............................................................................. 82
#44: ALL DE-SELECT.................................................................................. 84
#45: SQUEALING BRAKES ENABLE............................................................... 86
#46: FLANGE SOUNDS ENABLE.................................................................... 88
APPENDIX I: TROUBLESHOOTING...................................................... 90
QUICK EXIT GUIDE ..................................................................................... 90
Hard RESET (or QS-2+ Computer Restart)............................................ 90
All Select ............................................................................................... 90
Engine Unlock....................................................................................... 91
Operational Clear.................................................................................. 91
TROUBLES IN DIRECTION STATES................................................................ 92

TROUBLES IN RESET..................................................................................92
TROUBLES IN FORWARD AND/OR REVERSE...................................................95
TROUBLES IN NEUTRAL ...............................................................................98
TROUBLES WITH SOUND............................................................................101
TROUBLES WITH OLDER TRANSFORMERS....................................................105
TROUBLES WITH NEW TRANSFORMERS.......................................................106
APPENDIX II: CONNECTING TRANSFORMER & HORN/BELL
CONTROLLERS TO YOUR TRACK .....................................................108
CONNECTING THE TRANSFORMER TO YOUR TRACK ....................................108
CONNECTING THE LIONEL BELL BUTTON TO USE IN PLACE OF THE
TRANSFORMER HORN BUTTON...................................................................111
ADDINGPOWERTRAK TOYOUR LAYOUT .........................................................112
ADDINGSIDEKICK II TOYOUR LAYOUT...........................................................112
APPENDIXIII: QUICK REFERENCE CARD............................................113
APPENDIX IV: SYSTEM DESCRIPTION & HARDWARE
ADJUSTMENTS........................................................................................115
AC VERSUS DC MOTOR OPERATION .........................................................116
ADJUSTING THE VOLUME...........................................................................117
CONNECTING THE SPEAKER WIRES, THE COIL COUPLER & THE DIESEL
WARNING LIGHT.......................................................................................118
USING CABLES TO CONNECT POWERED DIESELS ........................................119
REPLACING THE BATTERY .........................................................................119
RECHARGING THE BATTERY.......................................................................120
APPENDIXV: OPERATING WITHOUT A BATTERY............................121
APPENDIX VI: USING THE LIONEL CAB-1/POWERMASTER WITH
QS-2+..........................................................................................................122
APPENDIX VII: GLOSSARY...................................................................124
WARRANTY .............................................................................................129
INDEX........................................................................................................130

6
ongratulations!
You are the proud owner of a QS-2+ the most sophisticated on-
board digital sound and train control system available. Add QS-2+ to your
locomotive and you have incredibly realistic sound, the hottest train features on
the market, and complete control of your engine, all from your standard or
electronic transformer. With QS-2+ you have compatibility with all popular
three-rail transformers. In the future you will be able to easily upgrade QS-2+
to add new sounds and train running features.
QSI is a pioneer in the area of on-board electronic sound and control and we
are committed to bringing you the best that technology has to offer.
This manual shows you how to enjoy all the QS-2+ sounds and train control
features. You'll find everything from basic wiring advice, to full descriptions of
QS-2+ sounds, to the nuts and bolts of using ID numbers to run your engines. A
large section of the manual fully describes the unique QS-2+ train control
features, with step-by-step directions. At the end of the manual are the
Appendixes, with a troubleshooting guide, glossary, and information about
special uses of QS-2+.
Use this manual with your engine on the track in front of you. You'll learn and
understand the sounds and control features much faster by using them as you
read the manual. Sooner than you think, you'll be a master at running the
extraordinary QS-2+!
C

7
Setting Up
This section describes the equipment you need for faultless operation of
QS-2+.
The MORE sections throughout this manual explain how to get even better
performance from your QS-2+. It is not required that you read these sections, but we
thought many of you would appreciate the additional information.
Equipment List
You will need—
•• A layout or a long length of straight track in front of you
•• An engine with the QS-2+ system installed
•• A transformer with a Horn or Whistle Button
•• A Bell Button is necessary for Passenger/Freight Announce-
ment, Engine Plus, turning the diesel warning light on and
off, and some Brake and Flange sound operations.
Note: If you are familiar with running QS-1, QS-2or MTH®
ProtoSound, you can operate your QS-2+™ equipped engine as you would
these other systems. If you are not familiar with QSI products, please read on
before starting your engine.
1

uSection 1 Setting Up8
How To Wire Your Transformer
Note: If you already operate LionelRail Sounds, or MTH® ProtoSounds®,
and the bell and horn button work properly, you can skip this section on wiring
and go directly to the next section.
For your horn button (or whistle button) to work correctly, wire your
transformer to the track as shown. This illustration shows the wiring for a ZW
transformer. You can connect the wire from the center rail to either the A or D
terminal, depending on which side of the transformer you like to use.
If you are not using a ZW, check Appendix II for wiring information for other
transformers.
Note: In this manual, the words "horn button" stand for either the horn or
whistle button on your transformer.
Wiring the Lionel ZW Transformer
to a CTC Lock-On Chip
Common
U
U
U
U
ABC D
1
2
To outside rail or
ground terminal

Section 1 Setting Up u9
MORE: QSI PowerTrak
PowerTrak is designed by QSI to do two things:
First, PowerTrak monitors the voltage on your layout. The brightness of the two bulbs shows the
amount of voltage. When you press the horn or bell button on your transformer, one light will become
brighter than the other, showing you the horn or bell signal strength. This is very useful information with
any transformer. And PowerTrak is much easier to use than a volt meter, since the lights are visible from
anywhere in a room.
Second, PowerTrak helps solve compatibility problems between MTH ProtoSound or Weaver
ProtoSound engines and Lionel's Cab-1 walk-around throttle and PowerMaster. ProtoSound engines and
the Lionel system are incompatible in two ways. First there are software problems, which are solved
when you convert your ProtoSound engines to QS-2+. This conversion can be done through QSI (call
for details). Second, there are hardware problems, which are solved when you add PowerTrak to your
layout. A switch on PowerTrak puts a resistive load on the output of your Lionel PowerMaster. This
load produces a waveform that QS-2+ converted ProtoSound engines can understand. Also, since the
Cab-1 walk-around throttle does not have stops or voltage marks on the red throttle knob, PowerTrak
helps you find the high/ low voltage settings you need to run QS-2+.
PowerTrak is also useful with older transformers that have weak horn signals. These weak signals often
can't be understood by QS-2+. The extra resistive load PowerTrak puts on the track makes the horn
signal stronger, often solving the problem. If PowerTrak doesn't solve your horn button problems, it's
time to have the transformer repaired.

uSection 1 Setting Up10
Connecting A Lionel Bell Button
A bell button is necessary for activating many QS-2+ train control commands.
You can also use the bell button to turn the bell on or off in any direction
except RESET.
If you do not have a bell button, attach a QSI SideKick II to your transformer.
SideKick II includes bell and horn buttons designed specifically for QS-2+. See
the next page for more information on SideKick II.
To connect the Lionel bell button, also called a Sound Activation Button, follow
the instructions shown below. (Your Lionel bell button instructions show the
same wiring.)
Note: If your transformer does not have a horn button, or the horn button is not
operating correctly, you can wire a Lionel bell button to blow the horn or
whistle by reversing the connections. You can also add two Lionel bell buttons,
one to run the horn and one to run the bell. See Appendix II.
Note: If you are using an electronic transformer (for example, an All-Trol, or a
Lionel MW or RS-1), the Lionel accessory bell button does not work reliably. If
you need a separate bell or horn button, connect a QSI SideKick II controller to
your transformer.
Red Wire
Common
U
U
U
U
A
B
CD
1
2
Black Wire
Wiring the Lionel Bell Button to a ZW
Transformer

Section 1 Setting Up u11
MORE: Lionel Horn and Bell Buttons
When you press the Lionel horn button, it applies positive DC to the track and tells the whistle to blow.
When you press the Lionel bell button, negative DC voltage is applied to the track, operating the bell. If
you have wired the bell or horn button backwards, instead of turning on the bell, pressing the bell button
may cause the horn to blow. You may have noticed that older Lionel engines using the mechanical horn
relay don't care which way the transformer, horn, or bell button is wired, since either the horn or the bell
button will cause the horn to blow.
MORE: QSI SideKick II
Run your engines effortlessly with QSI SideKick II.SideKick II is a simple, easy to use controller. It
attaches between your transformer and track. You can use the buttons on SideKick II in place of your
transformer buttons, eliminating problems with worn, faulty horn buttons or missing bell buttons. The
horn button operates older 1950's horns and whistles as well as newer ones.
SideKick II sends strong and reliable signals. No more missed messages between your transformer and
engine. Three buttons control your engine's horn, bell and direction. The fourth button gives the boost
your need to select RESET Features and program your QSI and MTH ProtoSound locomotives quickly.
Using this button to find the RESET Position you want is much, much faster and more reliable than
using the throttle on your transformer. SideKick II also makes it much easier to arm and fire ProtoSound
and QSI coil couplers, or to lock and unlock ProtoSound and QSI equipped engines.
And SideKick II performs flawlessly with any transformer. Many electronic transformers use a chopped
waveform to send signals to the track, which does not work well with most accessory horn and bell
buttons. The switch on SideKick II provides a stronger horn and bell DC signal, giving reliable
operation.
Once you try SideKick II, you'll wonder how you ever operated your engines without it.
Information about SideKick II is added to this manual any time using SideKick II makes running your
engines considerably easier than using transformer controls. Look for this symbol:

uSection 1 Setting Up12
The Back-up Battery
An on-board battery supplies continuous power to the QS-2+ computer and
sound system during power loss from direction changes, entering RESET, or
dirty track and faulty switches. The battery keeps the sound from shutting off
abruptly and unrealistically when there are momentary interruptions in track
power.
The sound will usually continue for five to ten seconds after the transformer is
turned off. This is normal. After about 15 seconds the battery power is shut off
automatically by the QS-2+ computer. The computer and sound will start up
automatically when power is reapplied.
The battery is a rechargeable NiCad (Nickel Cadmium) which is continually
charged from the track whenever the power is on. Unlike the old D batteries
often used for older Lionel horns, NiCad batteries are a dry battery and should
not leak or cause any damage to your locomotive. NiCad’s last up to five years.
The NiCad battery we use for QS-2+ is a special 7-cell, 8.4v battery, not the
more common 6 cell, 7.2 volt. Using a fresh, standard 9 volt alkaline battery
temporarily will not harm the system, and can be used while waiting for a
replacement battery. But 9 volt alkaline batteries cannot be re-charged by QS-
2+ and will run down. QSI and some specialty electronic parts stores carry
replacement 7-cell NiCad batteries.
Note: For more information on batteries, please read the section about batteries
in Appendix IV. If you intend to operate your engine without a battery for any
reason, read the instructions in Appendix V first.

13
Starting Up
Remove all other engines from the powered track. Place your QS-2+
equipped locomotive on the track and turn the power on about
halfway (below 10 volts). You will hear a double "ding" telling you QS-2+ is
up and running. You will also hear either steam compressor sounds, electric
cooling fans or a diesel motor starting up. You are in a special state called
RESET. Your engine will always enter RESET after the power has been
off three seconds (or more) and then powered up again.
Anytime you turn the power off, you will hear a time-out "ding" to let you know
three seconds have passed. When you turn the power back on you are in
RESET.
If the power is off for more than 15 seconds, the electronics shut down
completely. Now when you turn the power back on you will hear a double
"ding, ding." You are in RESET and the two "dings" tell you QS-2+ is up and
running correctly. This is called a "Hard RESET." Hard RESET is useful if
your QS-2+ computer gets stuck and will not respond to commands. "The
Quick Exit Guide" in Appendix I gives three more commands you can use any
time you find yourself in trouble with QS-2+.
Transformer Identification
With the throttle still at a low voltage setting (around 10 volts), pause for about
one second and listen for two brief air let-off sounds (“pssht-pssht”). QS-2+
uses this time to automatically identify your transformer. You can leave RESET
any time you like, but if you wait until your transformer is identified, the horn
and bell buttons will respond more quickly to your commands.
Wait one second for QS-2+ to identify your transformer.
Then interrupt the power to leave RESET.
2
pssht, pssht

uSection 2 Starting Up14
Changing Engine Direction
You cannot leave RESET until the power is turned to a low setting (below
10 volts). When the power is turned down, use the direction button or the
throttle on your transformer to interrupt the power and change direction as
usual. You are now in forward and have left RESET. You are hearing the
steam chuff, electric locomotive fans, turbine or diesel motor sounds of your
engine. Each time the power is interrupted the engine will sequence from
forward to neutral to reverse to neutral and then back to forward, just like
engines with mechanical E-units.
QS-2+ has five states. These include the four usual direction states (forward,
neutral-before-reverse, reverse, neutral-before-forward), plus our special
RESET state. When your engine is in RESET, you can change or program
individual features of your QS-2+ using your throttle, horn and bell button.
RESET will be described thoroughly in Section 4.
The Horn Button Has Many Uses
The horn button will blow the horn in forward and reverse, as it always has.
However, the horn button has other uses in RESET and neutral, since the horn
button is also used to operate QS-2+ features. These special uses will be
described in the following sections.
Forward
Neutral
Reverse
Neutral
RESET

Section 2 Starting Up u15
MORE: Multiple-Heading
Engines without QSI Reverse Units in multiple-headed trains tend to fight each other
Engines with QSI reverse units are easy to keep operating in sequence. To get out-of-sequence engines
back into sequence, reset your engines by simply turning the power off for three seconds or more
and then turning the power back on. All engines will come up in RESET. Now, when you interrupt
the power, the engines start out in forward and operate together.
Power Interrupt Delay Keeps Your Engines Working Together
A delay feature built into the electronics of QSI reverse units prevents your reverse units from 'dropping
out' or easily changing direction because of faulty switches and dirty track. Once these engines are in
sequence and working together, they will stay that way. Since QSI Reverse Units are designed to ignore
short power interruptions, you need to interrupt the power deliberately to change direction.

16
Sound
The following section explains how to operate all the different QS-2+
sounds. Many other sounds occur automatically when you are in neutral,
forward or reverse. These automatic sounds are described at the end of this
section.
Horn or Whistle
Blow the whistle or horn as often as you like as long as the engine is in forward
or reverse, but not while the engine is in neutral or RESET. (In neutral and
RESET pressing the horn button causes QS-2+ to perform special commands.) If
the whistle or horn does not blow, try pressing the horn button slowly and only
halfway. You can press the horn button for short or long periods to get short or
long blasts.
3
hoonnk!!
Forward or Reverse
Blow the horn or whistle in forward or reverse only
Forward or Reverse
Whoo-ooo!!

Section 3 Sound u17
Bell
To Turn the Bell On Or Off with the Bell Button
You must have an accessory bell button or SideKick II wired between your
transformer and track.
•• Press the Bell Button in forward, reverse or neutral.
If you go into RESET when the bell is on, it will stop ringing. (In RESET, the
bell button operates other features, described in Sections 5 and 6.)
To Turn the Bell On with the Horn Button
•• Interrupt the power to put the engine in neutral
Be sure you are not in RESET. If you are in RESET, interrupt the power until
you reach either of the two neutrals: neutral before forward or neutral before
reverse.
•• Put the throttle at a low voltage setting (below 10v.)
•Press and release the Horn Button
Your bell will stay on in all directions.
To Turn the Bell Off with the Horn Button
•Interrupt the power to put the engine in neutral
Put the throttle at a low voltage setting (below 10v.)
•Press and release the Horn Button
In other words, each time you press the horn button when you are in neutral
and the throttle is at a low setting, you will toggle the bell.
Your bell may continue to ring for a few seconds before stopping; this is
normal.
To activate the bell with the horn button,
put the engine in neutral with throttle
at a low setting and press the horn
button
NEUTRAL

uSection 3 Sound18
Coupler
To Arm and Fire the Coupler
•Put the engine in neutral (not RESET)
•Move the throttle to its highest voltage setting
If you are using an electronic transformer, such as an All-Trol, you may have to
bring the throttle down a little from the very highest setting.
•With the throttle still at the highest voltage setting, press and release
the Horn Button. The coupler is armed
You will hear the sound of the coupler drawbar lifting. The coupler is now
armed and ready to fire.
•Leave the engine in neutral or interrupt the power and run the engine
in any direction
•Press and release the Horn Button
The coupler will fire. The horn will not blow.
You can press the horn button to fire the coupler in any direction, but not in
RESET. The coupler will remain armed until you fire it, even if you enter and
leave RESET. If the power is off for more than 15 seconds, and the computer
shuts down, the coupler needs to be armed again.
Note: The difference between turning the bell on and off or arming and firing
the coupler is the position of the throttle. You need a low throttle setting (below
10 volts) to operate the bell, and the highest voltage setting to arm the coupler.
Caa-lank!
To arm the coupler, put the engine in neutral,
keep the throttle at high and push the horn button
NEUTRAL
Throttle at
high

Section 3 Sound u19
To Arm and Fire the Coupler with SideKick II
•Make sure the boost voltage on the transformer is turned all the way
up
•Put the engine in neutral
•Press the Boost Button
•While holding the Boost Button down, press the Horn Button
You will hear the "clang" of the lift bar, telling you the coupler is armed.
•Release the Horn Button and then the Boost Button
•Leave the engine in neutral or interrupt the power and run the engine
•Press and release the Horn Button
The coupler will fire.
Note: If you fire the coupler in neutral, you can continue to press the boost
button as you press the horn button. This extra power helps open the coupler.

uSection 3 Sound20
MORE: QSI Coil Coupler
If you install a QSI Single or Dual Coil Coupler Kit on you engines, the coupler (or couplers) will
actually open when you fire them. You will be able to uncouple anywhere on your layout, even on the
fly, by remote control.
The kits consist of a special coupler (or couplers), and a small circuit board that attaches with wires to
the top QS-2+ board. The QSI coil coupler is similar in design to the Lionel electromagnetic coupler
used in the late 1940’s. In fact, if your engine has the Lionel coupler, you can connect it directly to the
QSI Coil Coupler circuit board.
With a QSI Dual Coil Coupler Kit, both couplers can be operated by remote control. RESET Feature
#10 lets you program how the two couplers work. Both couplers can be operational, or you can choose
between the front or back coupler.
Contact QSI to order either the Single or Dual Coil Coupler Kit.
Once you install a Coil Coupler Kit, you can use the coupler in the following fun ways:
Uncoupling in neutral: This is the most prototypical way to uncouple cars from an engine. Pull to a
gentle stop, leaving a slight tension in the drawbar. When the slack is pulled out of the drawbar, it
allows room for the knuckle to open. On the other hand, when pulling heavy trains, the tension can be so
great that it binds the knuckle and prevents the coupler from opening. This is the same problem that
prototype railroads have and they will adjust the pull on the drawbar to allow easy operation. So if the
drawbar is pulled tight and the coupler will not open, try backing up a little to relieve the tension. Also,
leave the throttle at the highest voltage since this gives more power to the coupler circuit.
If you are moving only a few cars, the coupler will probably open if the draw bar is not pulled tight.
This allows you to position operating cars precisely in front of loaders and unloaders and uncouple the
car. Again, it's best to leave the throttle at the highest setting when opening the coupler to provide the
most power.
Uncoupling on the fly: After the QSI coupler is armed in neutral, the coupler can be fired in any
direction. Three-rail operators are familiar with opening the coupler while the engine is moving as it
passes over an remote control track section. The QSI coupler can also be operated while the engine is
moving and does not require a remote control track section. Once it's armed, the coupler can be opened
anywhere on the layout by pressing the horn button.
When pulling cars, the drawbar will be pulled tight so the coupler knuckle should have room to open.
When pulling heavy loads, the coupler may have too much tension and will not open. Running the
engine at a higher throttle sometimes helps since it provides more power to the coupler circuit. The QSI
coupler circuit board stores energy in a capacitor to use when the throttle is at a low setting, but
occasionally this is not enough power when there is a lot of force on the drawbar.
Pushing uncouple: Another way to use the QSI coupler is to open it when pushing cars to allow them
to coast onto a siding. This requires some skill and the right kind of engine and cars. The trick is to open
the coupler at the same time you lower the throttle to slow the engine. This allows the cars to put tension
in the drawbar and pull away from the engine. The cars should be easy rollers and the engine should
have the ability to slow down faster than the cars. Prototype railroads use this technique quite often. The
engineer controls the engine speed and the brakeman rides next to the engine coupler to open the
knuckle at the right time. Since the model train operator needs to do both operations at the same time, it
requires some quick thinking and fast reflexes, but the result is well worth the effort.