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?
"Digital Railroader" wrote in
news:j3HWe.49980$ snipped-for-privacy@tornado.rdc-kc.rr.com:
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.
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!
"Wolf Kirchmeir" wrote in message
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
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???
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...
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
On Sat, 17 Sep 2005 20:31:43 GMT, "Norvin (remove SPAM)"
wrote:
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,
Not at all, no problem. I realise that if one can't get close to the
real thing often, one's notion of what's realistic tends to get hazy.
It jumps: At every notch/run change, the engines rev up and noise level
increases. Takes a second or two. vrum-vrum-vrum ---> vruuuum --->
VRUUUM ---> VurAH-AH-AHM! (That's EMD 567s as near as I can phoneticise
them.) There's also generator whine and turbocharge howl that increase
at every notch. Who says diseasles are boring????
Plan your next vacation to take you near a busy main-line yard. It will
be worth it. If there's a shopping mall nearby, you can let the rest of
the goof off in air-conditioned comfort while enjoy your addiction in
peace. :-)
Back in the late 50s days, before sound-abatement efforts, a triplet of
F7s accelerating the CN's Super Continental westbound from the old
Edmonton station nearly deafened me. I was standing under the 105th St
overpass (now long gone) one track over from him, and the engineer
notched them up just as the engines approached me. Wow! Couldn't hear
myself yell! There's an old record around of a similar notching up of a
trio of FTs, IIRC: played at _realistic_ levels it will shake your
house, assuming you've got the amp and speaker power to do it right.
The Huron Central (operating subsidiary of Genesee Wyoming, formed to
lease the CPR line between Sault Ste Marie and Sudbury) runs about 150
yards from our house, down the street and across the highway. Usually
has three units, and they rumble real nice as they go by. He usually
notches up eastbound about the time he gets level with our street.
There's a slight grade, and he's dragging 50 or so loads, mostly steel
and pulpwood. Nice.
Hah!
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.
Then, the sound does change incrementally as "the engines rev up and the
noise level increases. Takes a second or two". I don't see how that could
cause an absolute "jump" from one notch to the next, as if the sound became
completely different at each new setting???
Well, my attempt at writing down how it sounds represents four runs, not
the transition from one run to the next. The --> is the transition, and
it really does take only a second or so for the engine to rev up from
one run to the next. If I could've figured a way of doing it, I would've
written eight versions of vrum instead of four. :-) BTW, I've heard an
engine rev through four notches while standing in the yard, took about 2
seconds.
From my trackside observations, when an engine is running in run 6,
say, it will sound pretty much the the same regardless of how fast the
train is actually moving. That is, a drag freight in run 6 may be moving
at 25mph, while a fast freight may be moving at 40. Run 6 produces a
certain amount of power, and that translates into different speeds with
different loads behind the drawbar. In fact, when the train starts,
first the engine revs up, and then the train begins to move. But I don't
know how tricky it would be to get that effect with a decoder.
Without actually hearing the sound in your decoder, I can't say how
realistic it is. But if it's based on actual sound recordings, I'd trust
the mfr, for the actual sounds at different run/notches, anyhow.
In any case, there should be eight steps, and it looks like the shift
from one level to another will just happen faster electronically than
mechanically.
HTH&GL
That's just it - this is MRC we're talking about, and I really don't trust
them...
Well, I still have my doubts, especially when it comes to steam, which has
no notches, and yet the Brilliance steam decoders are said to have "8 steam
chuffs", which, IMHO, is like saying it also has 8 notches, and that only
makes sense if you consider that MRC has always been behind the curve when
it came to supporting DCC's "speed steps".
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.