Double headers and top'n'tail

[andrewmay]

I've seen some of these loco-hauled trains and was wondering what the system was for operating these types of trains and how it worked.
Take the example of 2x37's top'n'tailing some mk2 coaches.

Thanks,
Andrew

 

[Craig]

Locos are fitted with a multiple working type. For two locos to work together they must have the same multiple working system fitted, for example class 37s and 40s both use the blue star system so could work together. Whereas a class 56 uses the red diamond system, so could not work in multiple with either loco.

To work double headed both locos need to be coupled together with the multiple working jump cables connected. To work in top and tail the coaches must be wired through to allow the multiple working cables on both locos to be connected.

There is also the TDM (Time Division Multiplex) system where a loco can be controlled remotely. For example a class 91 being controlled from the DVT.

 

[clagmonster]

Or the locos can be driven in tandem when coupled together. ie with a driver in each loco.

 

[TheSlash]

Or the locos can be driven in tandem when coupled together. ie with a driver in each loco.

I think this is banned now or highly frowned upon, not sure why. If the driver in the leading loco applies the brakes, it will apply the brakes on the other loco and the train and if the application drains enough air out of the brake pipe, the ECG will drop out and shut off traction power on the other loco

 

[andrewmay]

Thanks alot for this info. Could you tell me exactly how it works so like when the driver applies power in the front loco, what actually happens from the control desk and how does the rear loco recieve the message to apply power and also with braking. Be as descriptive and use as much technical language as you like.

Cheers,
Andrew

 

[47205]

Well, here is what they sometimes do:

The front driver applies power, causing the rear driver to then respond by picking up the rear of the train as well. hock: