[Ravenser]

The 108 is DCC ready, with a second socket in the trailer car.

I've used a pair of the Bachmann 3 function/2digit decoders to keep the cost down . It responds superbly - moving at a crawl at speed step 1

This is the best RTR DMU we've seen yet - better even than Bachmann's Turbostar which isn't DCC Ready. It features full underframe detail (engines , radiators etc) There's interior lighting , though its too dim to see in daylight , mouldings are crisp and detailed and windows are very flush and look good. There are NEM pockets , at the correct height, and 8 wheel pick up for reliable running

I haven't compared mine in detail against the drawings in Golding's book yet , but no-one has yet spotted any errors/distortions/issues with the model.

It's very very nice , and a snip at the prices it's going for.

One of Bachmann's best - and it breaks new ground as the first modern high spec RTR model of a Modernisation Plan multiple unit. One of those models that should sell steadily for years to a lot of very satisfied owners

 

[Ravenser]

doubleOO:

DMUs were made up in various ways , often within the same type. Bachmann have evidently modelled a motor/trailer 2 car set. There were definitely 3 car 108s and I think these had powered driving cars at both ends with trailer in the middle.

Some 2 car sets in some types were made up of "power twins" ie 2 x driving motor cars. The cl 110 "Calder Valley" sets modelled by Hornby were cases in point - the ex L&Y Calder Valley route across the Pennines being steeply graded

Yes the rear trailer had remote control of the engine on the motor car.

In fact being multiple units it went further than that - you could link several DMUs together and drive/control the whole lot from one cab at one end , provided the control systems were compatible - working in multiple . This is where references to "blue square" or "red diamond" control systems come in - there was a little symbol above the buffers on the cab end showing what control system was fitted , and only units with the same system could work in multiple. Thus diesel hydraulic DMUs could not work in multiple with diesel mechanical DMUs

Most first generation DMUs were diesel mechanical - a big bus engine of 150hp-230hp driving through a gearbox. Most second generation DMUs are diesel hydraulic

 

[Ravenser]

Now I'm at home and have access to my reference books, I can be a bit more specific.

There is a detailed table of vehicle numbers, types etc in BR First Generation DMUs in Colour by Stuart Mackay (Ian Allen , published just before Christmas and should therefore be available in bookshops) . Those Who Know say that this book is very accurate and that some earlier books on DMUs have quite a lot of errors in captions etc

Anyway it confirms bangerblueed's comments - only 5 x 3 car units, delivered to NEReg in 1958. There were however 6 x 4 car units , also delivered to NEReg in 1958. These units had both driving cars powered. The 4 car sets had a Trailer brake second with lavatory, a TSL and 2 x Driving Motor Composites, the 3 car sets had Driving Motor Brake Second, DMCL, and TSL.

According to Golding's book (Pictorial Record of BR DMUs, Cheona 1995) the body of a DMCL and the body of a DTCL are the same and the same drawings in the book apply , the difference is below the underframe

In other words , Bachmann need 1 extra vehicle for the 3 car unit (TSL), plus a new underframe for the composite and having done the 3 car they can build up to the 4 car with one extra vehicle (TBSL). At that point I'd imagine they stuff the mechanism in the central TBSL and you're up for 3 decoders

108 power twins seem to have been an LMR speciality, at least in the first instance: 12 2 car power twin sets in 1959, and a further 29 in 1960, with roof mounted 4 digit headcode boxes

108 2 car power/trailer formations, as depicted by Bachmann , were the most common 21 sets for the NEReg + 5 for LMR in 1958, followed by another 59 sets for LMR in 1959-60. A final batch of 21 for the LMR in 1960 had roof headcode boxes

The reason for power twins was presumably that 108s had 2 x 150bhp Leyland engines , whereas some other DMUs had 230hp Albion engines. There were some fairly steeply graded bits of the LMR in Northern England and presumably it was quickly decided power twins would be needed in some places. I remember toiling up the Long Drag on a Leeds-Carlisle local in the mid 80s on what I think was a 108, and Aisgill was cleared at around 45mph from memory. I assume that must have been a power twin - I doubt a power trailer unit with 150hp engines would have been let loose on that. This was before the S&C was full of heavy coal trains with Type 5s on the front - I doubt the operators would let an elderly lowpowered DMU struggle up to Aisgill today

If anyone's wondering why the ER missed out on 108s, initially - they had already 49 x 2 car 114 Derby Heavyweights based at Lincoln : these were 8 tons heavier, power/trailer sets and soon got upgraded to 230hp Albion engines