Is there ever a time when an engineer, with a stopped train, uses the DPU to push, before the head end? (maybe very, very gently?)
Back in the steam and electric days on the N&W, it was standard practice for the pusher engineers to open their throttles (advance their controllers) before the engineer of the lead engine.
DPU is likely to be another matter.
- Erik
I did it all the time when starting on hills, I’d have the DP engines loading in TH 2 or 3 as the
brakes were being released, then when I was confident the brakes were released I would
load up the lead consist and start the train, at the same time notch up the DP consist to the
next power notch,
What I was looking for. Thank you!
When a train has locomotives under power on the head end and on the hind end, the slack will be stretched on the forward portion of the train and bunched on the trailing portion. Where these two portions of the train meet, the mating couplers will not be in either compression or tension. Instead, they will just be loose with no load. I have heard that referred to as the point of “drawbar cleavage.” That point will be shifting forward and backward among the cars as the power outputs of the locomotives change from time to time, and also as the track profile goes up and down.
So, in starting, it makes sense for the helper to bunch up some slack in the rear portion of the train before the lead engine begins pulling, since that will be the natural condition when underway. Otherwise, the lead engine will have to take up all the slack in the train upon starting, and then the helper would have to take some of it back.
Starting up the DPU first when on a grade also keeps any slack from running out when the air brakes are released. It has happened where the slack ran out and snapped a knuckle when the air was released.
Jeff
Was this part of the “test”,[{] Mookie[}]?
Do you get extra credit if you don’t break knuckles, and the DPU is still coupled when you get there?
[:-,]
Y’know, Sam, I was watching a stopped mt coal train on a very slight short incline and watched an experienced engineer start that whole train with barely a ripple. I do so admire the people that can do that and make it look easy.
Which makes me also wonder - I am sitting there questioning so many different things about railroading - including, does the crew ever sit and have questions about the foamers? [alien]
If so, I’d bet most couldn’t be repeated here…
By notching the rear DPU’s out first, doesn’t this reduce the run out forces on the train when the lead units are cut in? I thought that I heard an engineer for the N&W, back in steam days, quoted as saying that this would not cause two “Bumps” on the cars in the trailing consist. Of course these were Y class Malleys, not AC4400CW’s, or ES44AC’s…
Correct me if I’m wrong.[:)]
-Justin