DMU's and carriages

[ReeceEmmitt]

Bear with me on this one - just wondering about the feasibility of something and thinking outside the box a bit. I am nothing but a interested commuter, so forgive me if there is any huge technical elephant traps.

Would it be feasible to connect a Mk 3 carriage to a Mk 3 derived DMU (for eg, a 150) to increase capacity as a short term expediency, or would the technical considerations/resultant impact on DMU performance be too significant to be overcome?

I look forward to your knowledgeable views.

 

[Emyr]

It wouldn't go very fast.

 

[455driver]

It would be dog slow, it would need rewiring to make it compatible with the DMU vehicles, it would need to be marshalled in the middle of the DMU otherwise it would be stuck when it got to the end of the line, you would need to rewrite the timetable to allow for the extra running times due to the lack of power etc etc.

Anyone who has driven a DMU with an engine out will tell you how sluggish they are!

 

[ReeceEmmitt]

Thanks guys - think the answer to my question is very clear.

Q: Would it be feasible to connect a Mk 3 carriage to a Mk 3 derived DMU (for eg, a 150) to increase capacity as a short term expediency...

A: No.

 

[The Ham]

Thanks guys - think the answer to my question is very clear.

Q: Would it be feasible to connect a Mk 3 carriage to a Mk 3 derived DMU (for eg, a 150) to increase capacity as a short term expediency...

A: No.

The answer was actually: Yes it is feasible, however it's also No it's not practical.

 

[Harbon 1]

I'm sure I've seen it happen with the 1st gen DMUs, and with EMUs on the Southern (for the boat train for extra luggage capacity) but its a lot more difficult now because everything used to have buffers and a standard coupling. I have one picture in a book of a two car DMU hauling a railbus coupled to a fish van!

 

[DownSouth]

The answer was actually: Yes it is feasible, however it's also No it's not practical.

I think what you meant to write was that it may be practical, but not feasible.

It could be done (i.e. it is a practical possibility) but the amount of money involved in doing it (and doing it right) would be so high that it would be a very unattractive move compared to other options (i.e. not feasible).

 

[455driver]

1st gen DMUs very rarely hauled an unpowered tail load, the boat trains were formed of 12 coaches (6 powered) and the MLVs were powered as well, okay there were GLVs which were unpowered but they were only used when another MLV would put the train over the CRE for the route.

We are talking about lengthening a normal (small) train, using examples of boat trains etc isnt really the same thing is it!

 

[DownSouth]

I'm sure I've seen it happen with the 1st gen DMUs, and with EMUs on the Southern (for the boat train for extra luggage capacity) but its a lot more difficult now because everything used to have buffers and a standard coupling. I have one picture in a book of a two car DMU hauling a railbus coupled to a fish van!

Worldwide, it's been going on since at least the 1950's when it would be common for a Budd RCD in a rural area to tow a van.

Today, the AK track recording cars (similar to the NMT in that they allow inspection runs to be done at full line speed) used on the 1435mm tracks in Australia still do their tours of the Sydney electric network by being marshalled into the consist of an older EMU class which uses proper AAR couplers and simple wiring along the train instead of complex digital data connections.

The catch is that you need much more than just the right sort of coupler, you need a EMU/DMU/DEMU with enough power to handle the extra weight, enough tractive effort to handle it with the gradients on the route, the right sort of setup for multiple working and so on. All practical to retro-fit to existing vehicles, but it's very expensive work and would provide little benefit.

 

[Harbon 1]

We are talking about lengthening a normal (small) train, using examples of boat trains etc isnt really the same thing is it!

I know, I know, I was using it as an example of how with older stock it would be easier as everything had similar couplings in one way or another, whereas now there are different coupling mechanisms which would make adding single carriages much more difficult as a concept before you even come to the feasibility

 

[Wolfie]

I know, I know, I was using it as an example of how with older stock it would be easier as everything had similar couplings in one way or another, whereas now there are different coupling mechanisms which would make adding single carriages much more difficult as a concept before you even come to the feasibility

.... before you get anywhere near software compatibility....

 

[455driver]

I think I worked out there are 25 different couplings in use today!
Taking into account coupler heights and electrical systems, I counted the BSI coupler (as fitted to 142-170s) as one coupler despite the 170s not being entirely compatible with the Pacers <quasimodo voice> its the bells!

 

[route:oxford]

You could probably just about get away with Chiltern's 121 hauling a coach (Mk1, Mk2, Mk3 or perhaps even Mk4)

 

[455driver]

You could probably just about get away with Chiltern's 121 hauling a coach (Mk1, Mk2, Mk3 or perhaps even Mk4)

That thing can barely pull itself, never mind a tail load!

 

[Murph]

I think I worked out there are 25 different couplings in use today!
Taking into account coupler heights and electrical systems, I counted the BSI coupler (as fitted to 142-170s) as one coupler despite the 170s not being entirely compatible with the Pacers <quasimodo voice> its the bells!

 

[sprinterguy]

That thing can barely pull itself, never mind a tail load!

Actually, the 121s were permitted to haul a tail load of one vehicle: A small number of unpowered driving trailers were built to accompany the 121s as required.

 

[455driver]

Oh I know that, I was referring to that individual vehicle!

 

[sprinterguy]

Oh I know that, I was referring to that individual vehicle!

Ah, fair enough!