EMD traction motors can take a lot of punishment (heat/strain), but like all mechanical systems they do have their limits. It's not speed per se, but amperage. Amperage=heat. You can only push so many amps through, and do useful work (turning axles) for a given time. Beyond those limits, weird shit has been known to happen. When a DC motor reaches its limits it overheats, then stalls.
This guy was pretty hard on his units, probably ignoring the load meter. But that happens... The old D-77, 78 motors will withstand overheat/overload for just so long. And when one goes, you're dead! The others can't do the job alone. They're in series configuration at low speeds, and just will not go! Takes a while ta cool 'em down before ya can go again.
This dude punishes his lead unit to the max! You take life out of 'em, and the wheels too, running thatta way!
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Hmm. That address doesnt look right. It looks like the link pointing here was faulty.
Yes Mr Krink, there is a load meter that displays the current going thru the #2 axle traction motor. It is adorned with a scale and a pointer needle that indicates amps in power and amps in Dynamic Braking (If equipped).
A main concern is surpassing design limits of the DC Components involved. So the scales are marked in increments starting at 0 amps and going up to theoretical melt thru. To the left the pointer shows dynamic brake value and a yellow range band topped by a red danger band. To the right the pointer shows a green power band topped by a red danger zone chopped into 60 min, 30 min, 10 min and 5 min areas. If you get to the 10 minute line you can run for 10 minutes after which you have to stop and follow the cool down procedure. Tu much operation in the red zones either way (Pwr or Dyn) generally result in fairly vigerous displays of spark showers and the dark toxic smoke of burning insulation.
Corse there are some exceptions to the rules...on the old Gonerail ex EL SD45-2's that were modified by PC for Helper operations between Conpitt and Alto the ammeter didnt have a red zone for Power. If you pulled the throttle out the wheels were going to move. Some old guys said the old covered wagons didnt really start pulling until they were in the red zone. For a while after the Gonerail merger you could always tell when you had Gonerail engines in yer consist because the brake warning light would cycle on and off during heavy downhill operations. Nothing to get worried about, but was fun seeing BOSS's expressions as he would reiterate the wild fluctuations of the load meter on a trailing unit after a schlep thru them.
Now, in this video ya have 2 gp38-2. Ya got 23 cars. So just grabbin for figures say 3500 tons. One engine otter pull that.
And how come no marker? Guess they used the red flag to flush toilet?
-- Edited by Calvin on Saturday 20th of January 2018 11:48:28 AM
Now, in this video ya have 2 gp38-2. Ya got 23 cars. So just grabbin for figures say 3500 tons. One engine otter pull that.
And how come no marker? Guess they used the red flag to flush toilet?
-- Edited by Calvin on Saturday 20th of January 2018 11:48:28 AM
I worked for a short line and remember similar scenarios. When I was a conductor there, I would do whatever it took to get the entire train over the hill because I was too lazy to make a cut and go back to get the rest.
As for no marker or flag, most short lines the FRA doesn't bother with. I know the one I worked at we never used flags or markers. No need to when you're the only train on the line.
