DMU coupling to EMU

[D7666]

No. There are so many technical differences between the two that it would simply be impossible. If EMUs and DMUs are intended to work together in multiple they would have to be designed for that possibility from the outset so that they have compatible systems.

O L Leigh

If that is a general NO to the whole question of DMU+EMU then that is wrong.

They do not have to be so designed.

All you need is a translator black box that does stuff like change gears on a DMU while controlled from the EMU, or EMU notch up when controlled from the DMU, and so on.

A modern sytem with a computer bus would ensure the respective tractive effort curves of the two train types to not fight each other by correct load sharing.

--
Nick

 

[Llama]

There is quite a bit more to it than that.

 

[30907]

There were such dual powered working on the combined Salisbury and Bournemouth line from 1966/1967 start of Bomo electric working right through to (?) May 1989 (?) I think that was the date.

None of these workings were anything to do with stock shortages. They were deliberate permanent diagrams. The precise combination of EMU - Cig / Vep / Hap with one or 2 TC and position of diesel in the train varied over years from timetable to timetable.

There was also a summer SO Swanage line working that had mixed diesel + EMU working. This also varied by year, and, believe it or not, was part of the same stock workings as the Salisbury line.


I found the Swanage working for summer 1967 :

10:47 ex-Swanage was 33 push 8TC to Bournemouth and forward 2Hap+73+8TC formed in that order to Waterloo. The 73 has to be coupled to the TC to light it.

There is some confusion in contemporary reports about these being 8TC or 7TC, anyway that does not detract from the interest.

Thanks for a fascinating piece of (slightly OT - I expected the Waterloo DML workings would appear somewhere in this thread!). I recall travelling with my family on the 10.47 and being surprised at the changeover from DL to to 2Hap+73 at Bomo. It was definitely 8TC on the day I travelled. (And disappointing by comparison with a WC and 12 ex Wareham in 1966!)

I had always assumed the diagram was a late adaptation due to the 74's not having been delivered, and don't recall other diagrams with 2Hap.

 

[ATW Alex 101]

I have also seen a video of a Voyager dragging a Pendolino, but I can't find it

Is this the one?

[youtube]HGPers-Te9o[/youtube]

 

[O L Leigh]

If that is a general NO to the whole question of DMU+EMU then that is wrong.

They do not have to be so designed.

All you need is a translator black box that does stuff like change gears on a DMU while controlled from the EMU, or EMU notch up when controlled from the DMU, and so on.

A modern sytem with a computer bus would ensure the respective tractive effort curves of the two train types to not fight each other by correct load sharing.

And what about the cab controls, fault indication lights and so on...?

Sorry, but you're so very wide of the mark. You cannot blend the tractive effort curves of different types of traction without a massive rewire and rethink of the traction packages themselves. You're talking about some sort of "plain sheet of paper" fantasy that has no relevance or bearing on the real world.

O L Leigh

 

[SpacePhoenix]

And what about the cab controls, fault indication lights and so on...?

Sorry, but you're so very wide of the mark. You cannot blend the tractive effort curves of different types of traction without a massive rewire and rethink of the traction packages themselves. You're talking about some sort of "plain sheet of paper" fantasy that has no relevance or bearing on the real world.

O L Leigh

Does it make any difference of the DMU and EMU are of the same "family"? For example a class 350 Desiro EMU and class 185 Desiro DMU?

 

[najaB]

You cannot blend the tractive effort curves of different types of traction without a massive rewire and rethink of the traction packages themselves.

Does it become any easier if only one traction package is actually going to be operational at any given time? Say you want to have lights, heat, door controls and brakes on both units, but only the diesel or electric traction is active at any point. Bonus points if it's possible to change between the two.

 

[cjmillsnun]

Does it make any difference of the DMU and EMU are of the same "family"? For example a class 350 Desiro EMU and class 185 Desiro DMU?

Not really. Things like the lighting, air conditioning and PIS may be compatible, but as stated as they have not been designed to work together then most of the systems won't talk.

Perhaps with software updates and rewiring it would be possible and faults could be displayed on a TMS, but the costs would be considerable for not much gain.

If the units are designed to talk to each other from the start (Voyager and Pendolino) then it's easier, but even then one will only couple to the other for emergency use, not in general service.

 

[upnorth71]

I have to agree with O L Leigh. For regularly scheduled operation of EMU+DMU, you need equipment that were designed for such operations from the outset. Here in Hokkaido, where I live, there is such a regularly operated revenue service that uses this setup. The DMU unit, the kiha 201 type, is powered by two 450hp engines per car, which totals to 2700hp per 3 car unit, which enables it to match the acceleration profile (2.2km/h/s) of the 731 series EMU it couples with. This, combined with compatible electrical and related subsystems, makes joint operation possible.

This video shows such a DMU unit arriving at a station, then the EMU from the opposite end, coupling up, and subsequent departure:
http://www.youtube.com/watch?v=vdhudIbzuLM