Automatic Couplers with Power Pass thru

[popeter45]

Random Question that passed my Mind
i know many Automatic Couplers like Dellner and Scharfenberg can carry Signals but do any either real or realistic proposed have the Ability to carry Power between units? (e.g. allow a Diesel Loco to power the traction motors of a EMU or let 2 EMU's share power via a single Pantograph)
is it even possible considering the current requirements of some units?

 

[hwl]

Random Question that passed my Mind
i know many Automatic Couplers like Dellner and Scharfenberg can carry Signals but do any either real or realistic proposed have the Ability to carry Power between units? (e.g. allow a Diesel Loco to power the traction motors of a EMU or let 2 EMU's share power via a single Pantograph)
is it even possible considering the current requirements of some units?

No and No

 

[najaB]

No and No

I'd say "No" and "Unlikely". As you note, the currents involved are quite substantial so designing a reliable auto-connecting system will be challenging. Not impossible though.

 

[AM9]

Random Question that passed my Mind
i know many Automatic Couplers like Dellner and Scharfenberg can carry Signals but do any either real or realistic proposed have the Ability to carry Power between units? (e.g. allow a Diesel Loco to power the traction motors of a EMU or let 2 EMU's share power via a single Pantograph)
is it even possible considering the current requirements of some units?

On EMUs the power provision is tailored to the needs of the EMU, and protected for any significant excesses. On Loco's the voltage levels would be far too high for a low level connector that when uncoupled is exposed to the elements. it's a bit higher than the standard trailer connecter fitted next to a car tow hook!

 

[D365]

Even if you take the high voltage/current requirement into account, significant design work would be required to ensure that the coupling could not be at risk of accidental energisation.

 

[37057]

I think the main problem would be finding a unit that has traction equipment (transformers for example) rated to provide power to additional units rather than designing a coupler that can transmit the power.

 

[jopsuk]

you could almost certainly build such a system, but it would also almost certainly be very difficult to retrofit it to any existing units

 

[plugwash]

The RIAB report on the caledonian sleeper brake incident said the original plan had been for full-auto couplers but they couldn't get ones that would take enough power for the hotel loads, so they ended up with a semi-auto setup.

And traction power would mean dealing with even larger power levels.

 

[supervc-10]

It's about cost vs benefit. I'm sure it would be technically possible to have an auto coupler that can take traction power, the question is whether it's worth it or not. Every unit will need a pantograph anyway in order to operate singly. The benefit would be if there is an issue with a unit's panto, or with higher speed running with multiple pantographs up on shoddy OLE.

There is a trend towards longer units these days- 10 or 5 car units are becoming common. There simply doesn't seem like there's a need for couplers with power passthrough.

 

[AM9]

It's about cost vs benefit. I'm sure it would be technically possible to have an auto coupler that can take traction power, the question is whether it's worth it or not. Every unit will need a pantograph anyway in order to operate singly. The benefit would be if there is an issue with a unit's panto, or with higher speed running with multiple pantographs up on shoddy OLE. ...

No, the technical issue wouldn't even make it operationally viable let alone have any cost benefit. The average 4-car EMU has between 1 & 1.5 MW of traction current requirement. An autocoupler with 25kV ac contacts would never be workable in a weather resistant configuration for reliability reasons, let alone getting safety clearance. So the next option would be to extend the bus between units. That impact of that would be:

The wiring and contacts would need a 2133A current capability.​

The on-board transformer/rectifier of every unit would need to be doubled in size as would the bus line (or duplicated).​

So all of that high-risk hardware on every unit would need to be balanced against the occasional need to recover a failed unit.
There is no problem with the very latest EMUs recovering their fellow units anyway, - because the class 700 Thameslink units are the only electric trains that can pass through the thameslink core, they have a capability to pull a failed unit out to clear the route. A 278 tonne 3.3kW 8-car 700/0 unit has sufficient power and tractive effort to recover a 410 tonne 12-car 700/1, even up the 1:27 ramps at each end of the core!

 

[supervc-10]

That's kind of what I mean @AM9

There is minimal benefit, and lots of negatives.

 

[edwin_m]

This proposal, no more than a concept at present, includes battery-powered wagons that are re-charged when coupled to a locomotive.

NGT CARGO | DLR Transport

The NGT CARGO trains will be composed of individual CARGO wagons and high-performance locomotives, as required. The individual CARGO wagons each have a built-in engine with lower performance as well as an energy reservoir on board. This means that they are able, autonomously and independently...

verkehrsforschung.dlr.de

.

The individual CARGO wagons each have a built-in engine with lower performance as well as an energy reservoir on board. This means that they are able, autonomously and independently, to serve sidings individually or as groups of individual CARGO wagons. Coupling and uncoupling of the trains takes place autonomously without the use of shunting locomotives or personnel. The individual CARGO wagons and locomotives are coupled together by automatic couplings which not only transmit locomotive power but also energy and signals.

 

[rebmcr]

This proposal, no more than a concept at present, includes battery-powered wagons that are re-charged when coupled to a locomotive.

I could just as easily make a flashy website about my idea for a supersonic airliner powered by the passengers' excercise bikes. As it so happens, the physics of our universe don't seem to pay much attention.

 

[najaB]

I could just as easily make a flashy website about my idea for a supersonic airliner powered by the passengers' excercise bikes

To be fair to @edwin_m, this proposal is on the DLR website rather than being a crackpot idea by a random guy on the Internet. If you're not familiar with DLR they are the German counterpart to NASA.

 

[Mordac]

To be fair to @edwin_m, this proposal is on the DLR website rather than being a crackpot idea by a random guy on the Internet. If you're not familiar with DLR they are the German counterpart to NASA.

I thought they were a light rail system in East London

 

[Philip Phlopp]

To be fair to @edwin_m, this proposal is on the DLR website rather than being a crackpot idea by a random guy on the Internet. If you're not familiar with DLR they are the German counterpart to NASA.

NASA do much in the way of autocouplers for trains then ?

 

[najaB]

NASA do much in the way of autocouplers for trains then ?

No, but they do a lot of basic technology research that finds its way into other areas. On the aeronautics side they are doing a lot of work on high-power electric systems for aircraft as are, I presume, DLR.

 

[Philip Phlopp]

No, but they do a lot of basic technology research that finds its way into other areas. On the aeronautics side they are doing a lot of work on high-power electric systems for aircraft as are, I presume, DLR.

I know DLR well - I've had to put a DLR logo on one of my/our presentations as they were involved in some way - I just can't remember what the presentation is/was or where I've got it saved.

 

[edwin_m]

I could just as easily make a flashy website about my idea for a supersonic airliner powered by the passengers' excercise bikes. As it so happens, the physics of our universe don't seem to pay much attention.

There's nothing in the laws of physics that would stop an autocoupler being designed that could transmit traction power. The issues would be more about safety and reliability in the "real world".

I'm not endorsing the DLR proposal, merely pointing out that the idea is out there (and one of our clients who has looked into it is taking it quite seriously).

 

[rebmcr]

To be fair to @edwin_m, this proposal is on the DLR website rather than being a crackpot idea by a random guy on the Internet. If you're not familiar with DLR they are the German counterpart to NASA.

Very well, but for better or worse they seem to have remarkably struck the same tone, style, and substitution of factual content with wishful thinking, that crackpot schemes like the Windsor rail tunnel project or the Essex tramway habitually do.

 

[delticdave]

Very well, but for better or worse they seem to have remarkably struck the same tone, style, and substitution of factual content with wishful thinking, that crackpot schemes like the Windsor rail tunnel project or the Essex tramway habitually do.

Q? What Essex tramway might that be?
(Interested Essex resident.....)

 

[najaB]

Q? What Essex tramway might that be?
(Interested Essex resident.....)

If you Google* it, you'll find that the proposal is to run a tram in an immersed tunnel between Ebbsfleet/London Resort (for points south) and Greys (for points north): https://kenextransit.co.uk/kenex-project/

*Other search engines are available but let's be honest: nobody is going to "Bing" anything any time soon.

 

[rebmcr]

Q? What Essex tramway might that be?
(Interested Essex resident.....)

There's a thread here https://www.railforums.co.uk/threads/£93-million-essex-light-rail-proposed.208733/ where it has been debunked — the quoted cost would cover a single-digit number of track-kilometres.