Steam locomotives each had an engineer in the cab to control the throttle and valve cutoff.
Diesel-electric and straight-electric locomotives are 99.999% of the time under "multiple-unit" control where they are electrically connected. Whatever control changes the engineer makes to the lead locomotive are electrically transmitted from the control itself to the lead and the trailing locomotives simultaneously. Most diesel-electric locomotives also have control circuitry that enables very different types of locomotives, when in multiple-unit configuration, to perform similarly, but there are conditions where the differences must be allowed for by the engineer.
Air brakes are controlled from the lead locomotive only in steam, diesel, and diesel-electric, with extremely rare exception.
RWM
Which brings up a question I have had forever. If you have a long train- say, a Norfolk Western coal train with a steam locomotive on one end, and a helper on the other- what means of communication were used to synchronize the efforts of lead locomotive and helper? Using the whistle comes immediately to mind, but how did a locomotive engineer on the lead end tell the back end to increase his "push"? No radios- no telephones that I am aware of- and a trainman standing on a caboose platform ready to pull a pin when the helper reached the top of the hill.
All I can come up with is that the engineer must have had some way of knowing when to push harder, and when to ease off- maybe by touch?
Using the whistle comes immediately to mind, but how did a locomotive engineer on the lead end tell the back end to increase his "push"?
Erik, It comes from experiance. Years and years of experiance. Something that really seems to get lost on everyone that asks this same question time after time is that these guys just didn't walk off the street into these jobs. And it doesn't have to be a steam engine. Even with diesels and radios, you would be very surprised at how little conversation goes on between two experianced engineers getting a double coal train over the road. If a train happened to get lucky and see clear signals all the way, you would hear nary a peep!
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I wholeheartedly agree with you, Big Jim. Experience is what makes the difference. But experience is really a series of procedures, rules, and events repeated over time that produce best results.
However, in the past, I've found that if they get a chance to think about it, experienced people can always explain how and why they did things the way they did. My most recent example was a locomotive engineer who stepped out of the change point office, glanced up and down his train, and shook his head. He mumbled "This is a dangerous train..." and when I asked him how he knew that, he gave me a laundry list of accurate observations. Along with, "Every train is different."
So, if I were able to find a live steam engineer and asked him how he pushed a train up and over the hills outside Roanoke, I think I would get a fairly detailed answer, even if it was specific to that one hill and one specific locomotive.
I know what you mean when the airwaves go quiet with modern engineers, but if asked right, they could probably state with authority what they were doing and why- and it would be more than "been doin this for a long time, sonny"...
they could probably state with authority what they were doing and why
That's very true. However, stating is one thing, typing is another. It is so much easier to carry on a coversation than it is trying to put into words something in a way everyone can understand it. Then there are the follow-up questions to deal with.
Pushing, done right, is nothing more than simple common sense. If you are only pushing over one mountain, such as Blue Ridge or Merrimac, you push as hard as you can to the top of the hill where the cab crew (when there was one) cuts you off. Now, the only single mountain (around here) is Merrimac, where the pusher engineer uses a "cut-on-the-fly device" that automatically closes the anglecock and pulls the pin.
Pushing over an entire district is a bit different in that you don't sit back there and push in the eighth notch all the way up the road and you don't push a man over the speed limit. you still need to know the road so that you know when to tighten up and when to ease up.
Im inclined to think that perhaps the lead engine simply took charge and marched off while the helper's job is to keep an eye on the train air gauge and work as necessary to keep it all moving.
Sometimes two sets of crews will learn each other during the operation. When that happens, they can be quite effective with a minimum of whistling or other communciation.
Im inclined to think that perhaps the lead engine simply took charge and marched off
Well, I wouldn't put it in quite those same words! There is coordination involved in getting the train started, be it whistle signals or radio conversation, etc. There is no just "taking charge and marching off"! That said, the lead engine/head end is in charge and it is up to the pusher to keep the slack in...and hopefully in a professional manner.
There is the story of the railroad president who had his private car coupled to a train run by an engineer with a reputation for a heavy hand at the throttle.
When they pulled into the yard, the president got out, walked up to the locomotive cab, and scolded, "You should know the speedometer in my railroad car registered 70 MPH, and the speed limit for this class of train is 59." The engineer responded, "Dad gum! Never did see you pass us."
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
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