What's up with multiple locomotives?

Question

I often see trains at crossings go by with two or three locomotives at the front. Are there occassions when more than one of them is pulling? And, if so, are they syncronized to pull together, or do they simply pull individually?

Answer 1

Well, I'm half asleep but I'll take a swipe at this.

Chances are most of the time you see multiple engines on a train, all are online and pulling, sans the occasional power swap or shop move event, where extra engines are tacked on the power to get to another location.

Locomotives can be "MU'ed" (Multiple Unit) via jumper and pneumatic cables, there by allowing the engineer in the lead unit control all the locomotives in the consist. Once the units are connected the engineer has control of the throttle, sand, etc.., in the lead and trailing units -- advancing the throttle in the lead unit to "Run 1" will advance all the units in the consist to "Run 1" and so on...they start to pull. Different company's engines and different unit models have different pulling/acceleration rates but it is still possible to MU them provided they have the right system which is pretty much universal nowadays, making for some interesting consists.

Heavier trains require more engines. Locomotives have a horsepower-per ton ratio based on the route they are traveling. And its not un-common for 2-3+ engines to be needed to move a freight (or passenger for that matter) train in a timely manner over the line.

Answer 2

It is more fuel efficient to run locos at half their power than full power. So it is more fuel efficient to run 2 locos with 50% power than one with100%. Also they are used for reallocation.

Answer 3

And if the weight they're pulling is big enough and they're headed over a mountain range there could be 4 or more locomotives. You see that often here in Calif as they head across the mountains into Nevada - a badass uphill!

Answer 4

The Train Company's just run out of room & they figure why pay 4 storage when they can B on the Tracks wasting fuel :->

Answer 5

Locos pull as needed.. it depends on where they're headed, and what kind of weight they are pulling..