Sutton's Locomotive Workshop British Railways Sulzer Type 2 Operating Manual - page 20
Light engine mode: Characteristics of an uncoupled or ‘light’ locomotive will be
quite different from when it is has a heavy train in tow. It will be capable of accelerating
and decelerating much more quickly whilst the power required to accelerate and
maintain speed will be significantly reduced. These changes cannot be successfully
simulated simply by changing inertia settings which, in any case, would have to be
adjusted when the loco is halted every time it deposited a train.
With a single press of F5, you can now alter the driving characteristics to that of
‘light loco’. Inertia is automatically, reduced, the thresholds at which the sounds change
are adjusted and the samples playing are amended. With small throttle increments the
idle sound will be held for the first portion of driving, enabling slow yard movements
(or similar) to be made without engine ‘revs’ increasing. Alternatively, large throttle
movements will produce a ramp-up for a few seconds initially, after which the engine
sounds will return to the level appropriate to the new speed.
This feature reduces inertia and momentum, as well as delaying automatic engine
power increases until higher track speeds are reached. F5 can be operated at any
speed to give another way in which the engine sounds may be instantly modified.
Note: This feature works best if you switch F5 ‘on’ or ‘off’ whilst the engine sounds are
playing in idle. Once switched, you can leave it that way, but any further change should
also be made with the engine sound again playing the idle sound. Just to be clear, the
actual speed is unimportant, but the engine sound must be idling. You can achieve this
in several ways as discussed earlier.
Power handle positions: In common with most British designs of locomotive,
the Class 24 power handle does not have fixed power level positions or ‘notches’, but
is continuously variable. There is, however, a tactile ‘notch’ to indicate selection of an
‘on’ position. There are also markings to show approximate power levels as follows:
OFF: In this position, the engine is idling only (and powering ancillaries etc.).
ON: Engaged prior to movement, this position connects the main generator to the
traction motors. This additional load causes the idling engine note to speed-up very
slightly to compensate. In layman’s terms, the loco is now ready to move. Indeed, on
level track, if the brakes were released, the loco could move slowly without additional
power needing to be applied.
QUARTER: Approximately a quarter of the power available. This is typically enough
to lift a light train on level track or for low-speed yard movements and shunting.
HALF: Approximately a half of total power. This is typically used for light trains on
slightly adverse gradients, or to provide an acceleration surge
THREE-QUARTERS: Approximately three-quarters of total power available. This is
enough to lift a heavy train on level track and the maximum normally required
when running ‘light engine’.
Coasting techniques: We’ve allocated F6 as the ‘Coast’ button. With this single
action you can dramatically affect the engine sounds being played. It will produce
different effects depending upon the speed of the loco, including when it is stationary.
When in motion, it will spool the engine sounds down to ‘idle on’ without affecting
the track speed. Use this to simulate ‘shutting-off’ prior to slowing to a halt or for
many other ‘coasting’ scenarios (for example, a heavy train on a downward grade).
Release the button and sounds will increase in power, according to the speed
currently selected.
Try leaving the F6 button ‘on’ after the loco has halted, and keep it on even when
driving off. The loco can now creep around with just an idling engine sound, great
for pottering around the shed or yard. Release it after speed has built up, however,
and the engine will instantly burst into higher power, the precise sound depending
upon the track speed and the status of F5 & F7 buttons.
Note: F6 takes precedence in its influence over sounds; if engaged, it will always cause the
engine sounds to remain at or spool down to ‘idle’. However, it has no impact on inertia.
There is also another way of ‘coasting’ without the need for any button presses. No
matter what actual speed your model is travelling at, or which engine power sound is
playing, reducing the throttle by 10 Speed Steps (of 128) will spool-down the engine
to idle, whilst the loco will continue travelling with a gradually reducing speed. This
coasting sound will continue until you accelerate; at which point the sounds will
change to those relevant to the current speed.
Notching-back power (step down): In most circumstances, the driver of a
locomotive will maintain the correct track speed by varying the engine power to
match the load, gradient and signal indications. Sometimes this will be by ‘coasting’
with the engine at idle and at other times by just reducing the power to a lower level.
Following the instructions outlined above will reliably simulate the former.
However, if instead of engine idling you would rather hear a slightly more powerful
note, you can do so at any time by
decreasing
the current speed by just one step on
your controller. The automatic ZIMO ‘notch back’ feature (sometimes known as
step-down) will instantly transition the sound playing to the next lower power band.
For example, if the loco is playing ¾ power sounds, reducing speed with your throttle
by one Speed Step will cause the sound to immediately spool-down to the sound
of ½ power. If in ¼ power, it will spool down to idle. If you operate with 128 Speed
Steps selected, this will be achieved
without any appreciable change in track speed
.
(Continued deceleration will not give further changes in sound until the speed
settings reaches the normal threshold which has been set in the project).
An
increase
of one Speed Step, or more, will immediately ramp the sound back up to
the higher power. So, at any given speed, it is possible, to toggle between two power
bands without perceptibly changing the speed. Talk about fine control!
SLW Class 24 Operating Manual
Page 39
Page 38
SLW Class 24 Operating Manual