Question about an EMD Diesel Locomotive?

Question

I know that various types of locomotive's produce different amount of horse power. Here's the question: A single locomotive (any type) about what would be the average speed it could gain in 0 to 4 seconds on take off.

Any smart A** answer will be reported for abuse, Thank you.

Thank You to all who answered my question. There all so good I'll let the public decide on the best!

Answer 1

Well, this depends on how the engine is operated.

If you release the brakes and open the throttle, on level ground, the engine will wind up and the thing will start to move, but not much acceleration for several seconds.

On the other hand, if "high speed" in shortest distance is the object, you'd keep the brakes applied when opening the throttle, it will load up, and as it starts to move (with the brakes still applied) then you release the brakes and it'll take off pretty quickly. I'd say you could get to 15 MPH in relatively short order.

This is the technique used when "kicking" or "dropping" cars.

In a kick, you get the car(s) moving quickly, the foortboard man pulls the pin, then the engine slows or stops and lets the car continue under its own momentum. Usuall, after a car clears, this allows the engine to enter another track, without having to push the car past the switch, stop, back up, stop, then head into the desired track.

A drop is a considerably more detailed (and tricky) move, that requires 3 people, including the engineer. This method is used to get a car into a track when the car is behind the engine.

In this instance, you again rap it up as quickly as possible, and upon signal use a little engine brake so the footboard man can get the pin, then accelerate again with the car rolling free behind the engine. When the engine clears the desired track, the third man, stationed at the switch, throws the switch to line the car into the proper track.

Tricky moves that require quick acceleration. That's how it's done. These techniques are not usually seen outside of local freight operations or yard moves.

There is an extra little trick, using the "generator field switch" on the control stand, which allows you to momentarily drop the amperage and still maintain speed of the prime mover (diesel engine). Open the switch to drop the load, close it and it'll load up again quickly.

Some carriers have outlawed these types of moves, and there is no provision in the tules for the generator field thing, so I wouldn't recommend either.

Addendum: Kudos to Highball and his answer below, but I need to make a small correction in the interest of accuracy.

A "Dutch Drop" is an archaic term descirbing an archaic move that is just never done anymore.

It works the same way as the "drop" described above, but, with a Dutch Drop, as the car is rolling free, the engine must stop, the man at the swutch lines it, and the engine reverses direction into the spur, with the man at the switch relining the switch to allow the car to roll by.

Answer 2

That's an interesting question.

They vary so much, dont know if there is an "average speed" that would be of any relevance.
I cant really improve on what has been said except to add a few comments.
as you might have guessed acceleration, all you can possibly get is very important at times.
Newer locomotives have taken most of the fun out of switching, too much computer controls.
With the older ones, that is what made the difference between just an engineer and a hoghead.
8 throttle (all you got) full independent brakes, relaese the brakes and close the generator field switch all at once was about the quickest move, not sure the speed you would get in 4 seconds but it would be too fast for a switchman to get on.
When I started on the Milwaukee in the early 70's, we still had the old electrics. If a switchman started getting cocky an engineer would make him a bet, he would say you stand right here at the front of the engine and i will take off, if you can catch the rear footboard I'll give you $10.00.
With a light engine he couldnt do it, those things took off like a rocket, they didnt have to build up any amperage waiting for the deisel engine to rev , the full line voltage was immediatly available overhead.
P.S., this has been very difficult for me not to be at least a tiny little bit of a smarta**, takes a lot of self control. LOL

Answer 3

Others here with more knowledge on diesel locomotive mechanics and operations can give a better answer but because most diesel locomotives, particularly road-switchers, are not rated/geared to accelerate that quickly in that small amount of time (now an electric locomotive is an entirely different story), I would guess no faster than between 10-20mph in the timeframe you noted, 0-4 seconds. Perhaps something like an EMD E-series locomotive (which is rated for speed carrying passengers) could make the best time but again, I would guess no better than maybe 20 mph in 0-4 seconds.

Answer 4

The two moves that Hoghead described are better known to me as the Dutch Drop and the Flying Switch. Letting a car roll like that without a locomotive attached to it is pretty sketchy, and in order for the move to work, you have to bottle the air. That's REALLY sketchy, but it's been done many, many times. Locomotives are totally capable of accelerating like that, but they'll definitely scream while they're doing it.

As a general rule, you just don't want to accelerate quickly with a train. The slack needs to come out gently and what not. If the slack is tight, though, I've seen some crews open it right up. A pair of GP39-2's must have hit 20 miles an hour in just a few hundred feet. I was really impressed by that one. I've found, though, that if you don't let the units load at their own pace, you just end up spinning the wheels or screwing something else up. You can also run into problems with the motors' transitions if you throttle up too fast. Not fun!

Answer 5

Hello Brian;
From my experience I would say anywhere from 15-20mph. 28 years of railroading. Switch engines don't have to spool up to start, whereas road engines rev up a lot before moving.
junkman

Answer 6

In only four seconds it might reach upwards of one mile an hour. It takes almost that to just get the revs up.

Answer 7

depending on the load--veeeeery slow--4 seconds it just about crawls..hope this isn't abuse