QSI QS-2plus!, Manual

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Section 3 Sound 24
Sounds in Forward and Reverse
1. Steam Chuff: When the QS-2+ equipped steam engine starts out, the chuff sounds are long with a
slow trail off. This is typical for steam engines where steam is applied for the entire stroke of the steam
piston to provide the most amount of starting force possible. After the engine starts moving, the engineer
will increase the “cut off” which only allows steam into the steam chest for a portion of the piston stroke.
This is more efficient but provides less low speed torque. In QS-2+ you will hear this effect as the engine
gains speed.
Steam engines produce four chuffs per wheel revolution which is close to what you will hear from your
QS-2+ engine at low speeds. When you increase the speed, the chuff rate gradually shifts to two per
wheel revolution. At high speed if the chuff stayed at four, the sound would become a blur. You can set
your engine to have a faster chuff rate (See Section 6, RESET Position #27).
QS-2+ produces four distinct chuff sounds per revolution, which give the distinctive four chuff cadence
familiar to most rail fans. A properly tuned prototype engine does not have this cadence and all chuffs
sound very similar. Since most operating prototype engines were out of tune, we have included this
familiar four chuff cadence in our sound system.
Mallet or compound locomotives have two steam engines mounted to a single engine body. The two
engines have their individual sets of chuffs and can be heard to go gradually in and out of synchrony.
This was usually due to one set of drivers not having as much weight over the axles so it would slip
slightly. The QS-2+ sound system uses two sets of chuff sounds to model this effect and at low speeds
you can hear the two engines change with respect to each other.
2. Diesel Roar: Diesels also make different sounds as they start up or accelerate. QS-2+ equipped
diesels are equipped with eight levels of diesel motor setting just like the prototype. When the engine
starts up, the diesel motor will rev up with a louder volume which will usually continue through the
acceleration period. After the engine has reached a steady speed, the diesel motor will taper off to a
constant roar at a slightly lower volume. If the throttle is again turned up, the diesel roar increases in
volume, will ramp up to a higher notch and then level off again. If the throttle is turned down, the diesel
roar will drop off slowly to one of the lower notch settings.
3. Electric Locomotive Traction Motors: Electric locomotives normally run quieter than diesels
allowing the whine of the traction motor to be heard. When you start out from a complete stop, you will
hear the whine of this motor increase in RPM’s until it fades out at a higher speed. You will hear the
traction motors again as you come to a stop. The traction motor sound is proportional to speed and not
voltage. So if you change the throttle setting the motor whine will not change abruptly. Instead it will
change only when the engine speeds up or slows down. The traction motor sound effect is quieter than
most other sounds and will be easier to hear if the volume of the cooling fans is turned down (see
RESET Position #6).
4. Electric Locomotive Cooling Fans: Although there is no prime mover to keep cool (as there is with
a diesel motor), electric locomotives nevertheless produce a lot of heat from the traction motors. Large
fans are installed in these engines to force air across the motors to keep the temperature down when they
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