How does double header train work?

Question

Sometimes you see double header or even triple header locomotives pulling long cargo trains. How do they operate? Do you have engineers in each of the locomotive and drive them separately or are they all controlled by the first locomotive?

More details would be appreciated.

Answer 1

The locomotives are wired together by computer (MU) (multiple unit) so that one engineer can operate 2, 3, 4 or more consecutive lovomotives. If the train has pushers at the rear, they need an engineer for that loco or locos.

Answer 2

The locos  coupled together have multiple unit control.Locos further down the train often have radio control so an engineer is not needed , just one at the front.

Answer 3

"Double heading" is an old term that was usually applied to steam locomotives, where there was a crew on each locomotive and each locomotive was ran coupled to but separate from the lead locomotive, which is where the control of the air brakes was, with the leading engineer.

Diesel electric consists are operated in "Multiple," adding additional power as needed from multiple unit "MU" operation.  All of the locomotives in the consist have their electrical control and air brake control systems linked by cable and air hoses to the leading locomotive.

The locomotives follow the commands given by the engineer together, as one engine.  So, even though there may be four locomotives in the consist, it is considered 1 engine.  On the railroad an "engine" is a unit propelled by any form of energy or a combination of units operated from a single control, used in train or yard service.

But, every once in a while, circumstances pop up, for whatever reason, that two locomotive consists (with two engineers) are coupled together, but not connected "in multiple."  In this rare instance, the lead engineer will handle his consist and the train, including air, with the second engineer running his consist, supplying only power.  He will follow what the lead engineer is doing.  This takes us back once again, to actual "double heading."

Helper engines, either placed within the train consist or behind the rear of the train, may have a helper engineer aboard or the helper is run by the engineer on the lead locomotive, sending radio signal commands which the remote locomotives will follow (hopefully.)

Answer 4

Pneumatic controls.

Thats what all those hoses are for between the units.