Do railroads use locomotives to transport… other locomotives? Sometimes, yes, but more often than not, that second or third locomotive is part of a modern rail technological innovation known as distributed power. As wireless technologies advanced in the s, freight railroads began adding extra locomotives to the rear of trains to give them enough power to climb steep hills.
This is how distributed power was born. Always looking to innovate, freight railroads evolved the use of distributed power through sophisticated onboard software and communications technology over the last 20 years.
Computers in both the lead unit and remote units also allow an engineer to coordinate braking and acceleration, as well as redistribute power as they see fit.
Distributed power makes trains more productive by allowing them to haul more. The slug cannot supply power on its own as it lacks a prime mover, it must be attached to the mother unit which supplies the power.
The purpose of the slug is to increase tractive effort, as the diesel locomotive oftentimes produces much more electricity than the traction motors can handle, resulting in wheel slip. The use of the slug gives the locomotive additional traction motors to more effectively distribute the electricity generated. There are different types of slugs for different operations, yard slugs are low profile to increase visibility while switching cars.
A road slug is commonly seen on local trains in the locomotive consist. These types of slugs usually have cabs and dynamic brakes for mainline use. It is common for road slugs to be rebuilt from locomotives that were formerly powered with a prime mover.
To maintain weight in lieu of the prime mover, the fuel tank is usually filled with concrete, which increases the tractive effort of the mother-slug pair. Another type of multiple unit train is when the entire consist is self propelled. These trains operate either by electric traction, or are powered by a diesel prime mover.
The electricity gathered from overhead wires or generated by the diesel engine is then sent to the traction motors on each car. These types of trains are similar to the multiple unit capabilities of a locomotive, however, the power generated is transferred throughout the entire train, instead of just the locomotive.
Many of these types of multiple units operate as a married pair, and is semi-permanently coupled to the car that houses either the diesel engine or the pantograph. An example of this would be the Metro North M8 train sets, where the electric current is either gathered by a third rail or the pantograph, and is distributed throughout the entire train set.
Another example are the new Eurostar train sets, the es, which are set up as electric multiple units EMUS. Additionally, most subway systems around the world use this type of traction for power as well, as it is more economical for use underground.
Most multiple units are used in passenger operation, as they are economical and easy to turn around at the end of a run. However, some freight carriers throughout the world use these train sets in their daily operations as well. This is due to the fact that most freight trains in North America operate with at least two locomotives in the consist. This was not always the case however, as during the early days of dieselization, locomotives from different manufacturers were not compatible.
Additionally, many early diesels were not delivered with multiple unit capability, and was added later. In the United Kingdom, a similar practice was adopted, however, some locomotives are not compatible with others.
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 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" 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.
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"!
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 Never did see you pass us.
Our community is FREE to join. To participate you must either login or register for an account. How do they syncronize locomotives views. Order Ascending Order Descending. Member since April , posts. I am new to model railroading and learning something new every day.
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