I was looking over the specs for MRC's new Brilliance sound decoders and
balked when I came to this statement, "synchronized diesel engine sounds
with eight notches"... That means the engine sound only changes every 16
steps!? Looks like a reluctance on the part of MRC to truly live up to their
promise that these decoders are brilliant! Any thoughts?
Presumably that corresponds to the 8 notches on a prototype throttle.
Broadway Limited's factory decoders have 8 distinct throttle steps.
At least the one in my E7A does.
--
===========================================================
Norman Morgan <> http://www.norm-morgan.com
I watched a crew run a train and I assume they needed a speed that was
somewhere between two notches because the engineer was toggling the
locomotives between the two notches. Sounded interesting as the engines
would rev up then slow down but the train maintained a constant (slow)
speed.
I'd be interested to know if the 'notched' decoders have the lag often
found on the real thing. Ie) Locomotives notch up but the train does not
immediately speed up. Alternately, the engineer may back off a couple notces
and the train keeps on going at the previous speed.
Jb
wrote in message
The prototype has eight notches or "runs." "Run eight" is top speed.
Go trackside near the exit from a yard, and listen as the engineer
notches up the engines. Impressive!
OK - since I can't do that, can you tell me - do you hear a gradual change
in engine noise, or does it jump higher with each notch and remain at that
level until the engineer moves the throttle to the next notch? Remember, I'm
asking this sincerely, I'm not trying to be a wiseguy...
| OK - since I can't do that, can you tell me - do you hear a gradual change
| in engine noise, or does it jump higher with each notch and remain at that
| level until the engineer moves the throttle to the next notch?
Distinct "jump." Remember the diesel is powering a generator that is doing
the real work. The notch setting the engineer is using is related to the
amps of current necessary to do the work. Amtrak's F40's would be at run 8
in the station because of the current needed by the passenger cars.
CTucker
NY
Are you sure that a F40 would be running at run 8 in the station? Since
the locomotive needs to keep a "small amount" of pulling power to the
train in order to keep the cars stretch during any braking. Air brakes
act on the rear car first and then moves forward. The engineer will have
to keep relieving the engine brakes to allow the stretching action to
take place.
Another thought regarding "8 notches" is that this is only referred to
the road locomotives. Switchers have no notches, just free wheeling on
the throttle. Of course this is all based on when I worked for the
Santa Fe and Southern Pacific on the west coast over the "loop".
| > amps of current necessary to do the work. Amtrak's F40's would be at
run 8
| > in the station because of the current needed by the passenger cars.
| Are you sure that a F40 would be running at run 8 in the station?
It had to do with the HEP - head end power - which fed off the prime mover.
Locomotives that supplied the HEP had to turn fairly consistent RPM's. And,
yes, they are very loud at the station. I've never heard one in an enclosed
station, but in the outdoor stations you can't hear yourself think. Whereas
freight trains are all but silent on the other track.
CTucker
NY
Full RPM, yes, but not full power. These could vary the number of
cylinders in use with power demand. When just running HEP (IIRC) they
only used four cylinders. And, the main traction generator was not in
use at all (though turning with the rest of the 'stack').
Dan Mitchell
===========
Yes, it brings up a good question - I have a Broadway NW2 on order, with
sound, and I'm wondering how it will handle the sound with no distinct
notches???
No it doesn't. once the train is stopped the throttle goes to the idle stop.
Most
likely it was already there before the train stopped. The engine brakes are kept
bailed off such that the braking is all done by the cars, inertia keeps the
weight of
the engines pulling against the coupler of the first car
Nope, its' around the other way. The air valve that is relieving pressure on the
train line is in the locomotive, not on the rear car, thus the initial pressure
drop
occurrs at the point of release, and propagates to the opposite end of the line,
such
that the brakes on the rear car are the last to release and the last to apply.
This is somewhat applicable to handling a freight train, but doesn't apply much
to a
passenger train, especially the short trains that are the norm these days.
There is
very little slack in a consist of six or seven passenger cars; so little, in
fact,
that it is not noticeable.
I have spent thousands of hours in switchers, from S-2s to SW1500s. I've operated
Alcos, Baldwins, EMDs and Fairbanks-Morse, and I've never seen one with a
notchless
throttle. Maybe you saw dynamic brake controllers that were notchless, but not a
throttle.
The best guess for the FP40 and its attendant high RPM at rest, is that the
engine is
kept running in notch 5 to provide Head End Power for the train. Speed control
is by
changes in excitation to the MG, while engine speed remains constant. At notch 7
the
engine speed either goes to max, or is linked to the throttle setting. While I
have
never operated an FP40, I have operated locomotives that were configured to work
in
that way.
Froggy,
Froggy wrote:
>> ...... Air brakes act on the rear car first and then moves forward.
>>
>>
>>
> Nope, its' around the other way. The air valve that is relieving
> pressure on the train line is in the locomotive, not on the rear car,
> thus the initial pressure drop occurrs at the point of release, and
> propagates to the opposite end of the line, such that the brakes on
> the rear car are the last to release and the last to apply.
Froggy, what brake schedule do loco-hauled passenger cars currently use?
When visting the US some years back I saw some cars with HSC schedule
equipment - is this still used? Are there any operators using
electro-pneumatic brake on loco-hauled stock?
All the best,
Mark.
Don't know Mark. I no longer drive trains and haven't for quite some time. My
interest in things railroad does not extend into the minutia of things such as
the
inner workings of air brakes, especially in today's context. That does not mean
that
I do not know how to use air brakes, or what makes them work, it just means that
beyond describing the engine driver's duties and actions in the use of brakes in
the
handling of a train, I should leave more detailed explantions of the interior
workings of the things to the people who actually maintain and repair them. I
have a
bunch of air brake manuals from Wabco, New York, and others that I have collected
over the years, but I have never found them to be especially interesting
reading. I
have a friend who still works for NS. He is a former engine driver who now works
in
the car department. He can answer all your questions. I will ask him when I see
him
next weekend and post the reply later.
Froggy,
I've enjoyed reading your insights here. The only railroader in my
family, my granddad, passed away nearly 30 years ago. 30 years and
I still miss him like it was yesterday!
He spent over 50 years working for the L&N (1908 - 1959).
--
===========================================================
Norman Morgan <> http://www.norm-morgan.com
OK - if that is the case, I suppose a change in sound every 16 steps is
according to prototype. Would that also be the case with steam engines? I
ask because MRC has similar wording for their Brilliance Steam Decoder - "8
steam chuffs", I believe...
"8
steam chuffs", I believe..<
Not sure what they would mean by this for a steam engine. Steam would
not have any steps but a steady increase related to speed. Probably ad
writers who have no idea what they are talking about.
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