EMU/ DMU Set Formations

[brel york]

When 156468 & 490 were damaged in the 1995 Ais Gill crash the good cars from each unit were formed together for a while. As neither contained a toilet they were confined to the Doncaster - Adwick shuttle. 150209 is formed of the surviving vehicles from 150209 & 212. Again neither has a toilet although it is in for refurb at the mo and so may have one fitted.

Many 150/2 units were split in the 90’s and the individual vehicles were formed in the middle of 150/1’s to form 3 car units. All are reformed back as 2 car units.

Northern’s 3 car 158’s have a centre car from a diffferent unit from the ex TransPennine 158 fleet.

150 209/212 is not having a toilet fitted during prm work

 

[Neptune]

That’s news to me but it might be Wikipedia inaccuracy.

It gained a driving car from 507022. It was given an experimental refurbishment by SPTE with high back seats and modernised draught screens but I believe it reverted to the standard low back seats when the refurbishment of the full fleet wasn’t taken forward.

 

[norbitonflyer]

If that was the case how was it driven to North Berwick? Scr didnt have many DTC's.

Hugh Longworth's catalogue of DMU formations lists nearly ninety ScR twin units in 1967, of what are now known as classes 100, 101, and 105, so there were certainly DTCs around then. Although when I first started observing such things in 1971, ScR units were almost all three car, many had a DTC in the middle. I can quite imagine a scratch formation could have been made up with two DTCs at one end, and I read of something of the kind happening at Glasgow Central, with a long ECS formation run into the station and split to form two service workings, the unit nearest the stops then discovered to have no engines.

A similar story is said to have happened at Woking once, when a the rear unit of an up Bournemouth Express was requisitioned to form a special to cover for a gap in the service to Alton. Only after the rest of the train had departed for London was it realised that this wasn't such a good idea, and a 33 had to be rustled up from somewhere to remove the "dead" TC unit which was now blocking the up fast.

 

[61653 HTAFC]

Was given to heavily corroded 144008, the centre car of 144021 was also corroded

144023 spent about a year as a two-car set after the centre car caught fire near Rochdale in 2013.

Re: the post above, DTC suggests an unpowered cab car (Driving Trailer Composite) so I wouldn't have thought such vehicles would be placed in the middle of formations in normal circumstances.

 

[Metal_gee_man]

Just remember the work, the effort and the cost of turning the former Gatwick Express class 460s Junipers into SWR class 458s, it wasn't just take the end driving vehicles off and insert carriages into the formation, it involved moving traction equipment, electrical systems, regearing to 75mph etc... It is a much harder thing to do with EMUs than DMUs as is proved when you see a pacer, and a sprinter connected and working in harmony.

I would guess the insertion of Coach U into the class 390s was designed in such a way that it had no duplicate specialist systems and has very little to do in Limp home/recovery mode to make things simpler!

 

[61653 HTAFC]

Just remember the work, the effort and the cost of turning the former Gatwick Express class 460s Junipers into SWR class 458s, it wasn't just take the end driving vehicles off and insert carriages into the formation, it involved moving traction equipment, electrical systems, regearing to 75mph etc... It is a much harder thing to do with EMUs than DMUs as is proved when you see a pacer, and a sprinter connected and working in harmony.

I would guess the insertion of Coach U into the class 390s was designed in such a way that it had no duplicate specialist systems and has very little to do in Limp home/recovery mode to make things simpler!

That's less about DMU versus EMU, more about modern stock having various computerised systems and/or software that are less likely to be compatible with stock from another manufacturer or era. Just as all 1980s DMU stock can work together regardless of who built it, the same applies to EMU stock of the same era.

With hindsight the 458/5 project units will end up being scrapped before they're life expired, but they aren't the first fleet to suffer that fate: plenty of modernisation plan diesels (both locomotives and units) were withdrawn early due to being non-standard.

 

[norbitonflyer]

Re: the post above, DTC suggests an unpowered cab car (Driving Trailer Composite) so I wouldn't have thought such vehicles would be placed in the middle of formations in normal circumstances.

Probably declassified when used in that way, but yes, I did notice in particular that there was a cab in the middle of these units. (or, if you care to view it that way, a twin unit with a DMS attached to one end. Such formations have not been unknown in other contexts - anything from LUL C-stock to temporary 3-car class 150s and 158s to the "3T" (class 204) demus formed from "2H" units with an ex-2EPB driving trailer inserted in the middle (those driving trailers having previously been the "heads" of the class 206 "Tadpole" units, each formed with two cars from a "6S" (class 201) Hastings unit).

 

[plannerman]

Back in the early 90's (?) I remember several 2-car DMU's made up of one 156 car and one 158 car coupled. It was to do with brake issues with the 158's.
There's a picture of one (not mine) at the top of this page http://www.penmorfa.com/Archive/sixteen.htm - the link is to an excellent site regarding North Wales railways

 

[NotATrainspott]

Just remember the work, the effort and the cost of turning the former Gatwick Express class 460s Junipers into SWR class 458s, it wasn't just take the end driving vehicles off and insert carriages into the formation, it involved moving traction equipment, electrical systems, regearing to 75mph etc... It is a much harder thing to do with EMUs than DMUs as is proved when you see a pacer, and a sprinter connected and working in harmony.

I would guess the insertion of Coach U into the class 390s was designed in such a way that it had no duplicate specialist systems and has very little to do in Limp home/recovery mode to make things simpler!

You'll notice that one of the extra carriages in an 11-car Pendolino has a pantograph well but no pantograph. That's because it's functionally the same as one of the other pantograph+transformer carriages in terms of providing power to the other extra carriage, but a third pantograph wasn't required. As I understand it, it's essentially possible to continue adding carriages to the Pendolino design in chunks of 3 or 4 so long as they have the right arrangement of transformer and motor vehicles. There's a 25kV bus running along the top which means any extra transformer carriages can take power from the existing pantographs.

Plenty of longer fixed formation trains work in a similar way, since there's little point in designing a traction package for large numbers of vehicles. Any time you want a long train, you'll also want duplication of critical parts like pantographs and transformers anyway. Designing a traction package for approximately 4 carriages means you can easily re-use it across different train orders for different requirements. As I understand it, the Eurostar 374s have effectively 4 separate traction packages. Each 8-car half-set (being a fairly standard Siemens Velaro D train but with a cab at only one end) has two traction packages powering 4 carriages each with a 25kV bus connecting them.

 

[Taunton]

The modernisation plan dmu switch-arounds varied by operating region. The North Eastern in particular seemed to regard everything as loose, and you saw all sorts of individual vehicles standing in depots. The Scottish had a mad period in the 1970s, as alluded to above, just when I was in Edinburgh, and a 3-car set with vehicles from three different manufacturers, all driving, and some loose hanging gangways, became normal. The LMR was rather more strict and the Western even more so for the power cars, which on 3-car sets were commonly still with their delivery partners after 25 years. Their trailers, however, were all mixed up between these. I am guessing this all reflected different regional practices in managing the records.

 

[61653 HTAFC]

The modernisation plan dmu switch-arounds varied by operating region. The North Eastern in particular seemed to regard everything as loose, and you saw all sorts of individual vehicles standing in depots. The Scottish had a mad period in the 1970s, as alluded to above, just when I was in Edinburgh, and a 3-car set with vehicles from three different manufacturers, all driving, and some loose hanging gangways, became normal. The LMR was rather more strict and the Western even more so for the power cars, which on 3-car sets were commonly still with their delivery partners after 25 years. Their trailers, however, were all mixed up between these. I am guessing this all reflected different regional practices in managing the records.

Different routes also had different requirements, such as the Calder Valley which had the more powerful class 110 sets specified for it, and any other sets working that way required at least two powered cars for every three cars in total. Less demanding routes would often get 3-car sets with only one motor car.

 

[Jona26]

After the close encounter of train v cement mixer at Oxshott in 2010 one of the damaged coaches from the electric class 455 was replaced with a coach from a diesel class 210.