DMU crossfeeding

[Augustas]

Can someone explain how crossfeeding works in a DMU.

 

[randyrippley]

I suspect you may need to elaborate over what you mean by "crossfeeding"

 

[Sun Chariot]

I suspect you may need to elaborate over what you mean by "crossfeeding"

Isn't it where two travelling mothers milk feed one another's babies?

 

[Wyrleybart]

I suspect you may need to elaborate over what you mean by "crossfeeding"

I think he means that some multiple unit trains can feed power from car to another.
So if a class 170 loses it's alternator on the leading car, the car can still receive electrickery from the vehicle(s) behind it. The driver obviously needs lights, horns cab displays etc as well as power for air compressors and HVAC. ISTR the ex Central Trains fleet of 170s had differences between the 170/0, 170/1, 10/5 and 170/6 but some of these were modified.

Not sure what other fleets of diesel units have

 

[CAF397]

185s can crossfeed

 

[dooton]

168/2's and 172's can also cross feed. An AC feed is sent from another vehicle in the formation to the SCU (static converter) in the vehicle being crossfed. Both vehicles will go to half lights and half HVAC as a result. A good get out of jail free card if you lose an engine.

Compressors on turbostars are on the engine and mechanically driven so if you lose the engine you lose the compressor so rely on main res being built by the other vehilces in formation.

 

[dk1]

170/2s were never fitted with cross-feeding regretfully hence the use of a bardic/emergency head or tail lamp occasionally. Always seemed penny pinching not to have it considering using a bardic back in the day meant 20mph.

 

[Augustas]

I think he means that some multiple unit trains can feed power from car to another.
So if a class 170 loses it's alternator on the leading car, the car can still receive electrickery from the vehicle(s) behind it. The driver obviously needs lights, horns cab displays etc as well as power for air compressors and HVAC. ISTR the ex Central Trains fleet of 170s had differences between the 170/0, 170/1, 10/5 and 170/6 but some of these were modified.

Not sure what other fleets of diesel units have

Thanks, just the answer I was looking for

 

[Towers]

Known as ‘Remote Supply’ on some BR era units, usually a circuit breaker switch in each cab. It’ll draw power from an adjacent vehicle for basics like lighting. This may be a much less complex and comprehensive system than what is likely fitted to newer fleets!

 

[Tomnick]

Known as ‘Remote Supply’ on some BR era units, usually a circuit breaker switch in each cab. It’ll draw power from an adjacent vehicle for basics like lighting. This may be a much less complex and comprehensive system than what is likely fitted to newer fleets!

Not even internal lighting, just the absolute basics of marker and tail lights, supply to driving controls (i.e. train wires). I've always understood it to be just a common power supply for those circuits that don't draw much power, carried between vehicles via jumper cables, rather than a complex crossfeeding arrangement that's switched automatically on demand. You can feed a headlight from it too, but only by operating a switch protected by a glass seal – presumably that's asking a bit much of the supply in normal operation!

I understand that, on 170s without crossfeed arrangements, you can't even supply the driving controls from an adjacent vehicle, so once the batteries are completely dead on that vehicle, it's game over from that cab at least (I've been there with a 158 with completely flat batteries on both vehicles. Couldn't couple electrically, so had to be just coupled mechanically and shunted as a swinger – all good fun!)