Could Gen 1 DMU’s operate as a single car unit (excluding 121 etc)

[ZephyrKN]

Late last night a thought crossed my mind and I’ve been unable to find a concrete answer so here goes, let’s take a class 101 DMU for example, if we split it in half so there’s just 1 car with an exposed gangway at one end would it be able to run? Or is there integral equipment connecting the cars together that would mean it wouldn’t work? I understand many DMUs had a driving trailer that was unpowered so of course that wouldn’t work but I’m curious if the power car would run as normal or not? I understand this is a rather pointless question but I would love an answer to satisfy my curiosity. I would also love to know if this has ever happened and if there’s any photos of it.

 

[Gloster]

Yes, I have signalled one in the dark hours of the night. It was probably a Class 118 and was running, I think, from Bath Road to Laira, probably because of a temporary shortage. But it was unusual.

 

[LowLevel]

Yes, they're entirely capable of running independently. Usually on depot transfer moves or similar. You could also for example couple a driving car with a gangway on to the cab end of another unit, there was no need for the corridor connection to actually be used.

As it happens 15x DMUs can also run independently if necessary for shunting or whatever, it's only later builds where you got into things like only certain vehicles having compressors.

 

[norbitonflyer]

I have seen a 114 power car run on its own - it was being sent from Lincoln depot to turn on the Boultham triangle - presumably to pair up with a driving trailer facing the wrong (i.e. same!) way

 

[Bikeman78]

Yes, they're entirely capable of running independently. Usually on depot transfer moves or similar. You could also for example couple a driving car with a gangway on to the cab end of another unit, there was no need for the corridor connection to actually be used.

First North Western did that with some class 101s towards the end. They attached an extra power car to some of the power+trailer sets. In other words, all three cars had a cab, rather like some of the current GWR class 158s.

Chiltern had lots of strange combinations too. Plenty of gangwayed vehicles attached to no gangwayed vehicles.

 

[Taunton]

A single power car would need to be one with a guards' compartment as well, otherwise it could not be belled away.

The Scottish Region had a surplus of 2-car units after the 1974 WCML electrification in Glasgow, so scrapped some of the driving trailers and used the power cars to add to other 2-car sets, giving two power cars out of three instead of one out of two. They were done indiscriminately by type, and it was not unusual to find sets from three different manufacturers. One bizarrely had a onetime Western Region single "bubble car" in the middle, a Gloucester RCW power car on one end, and a Met-Cam driving trailer on the other; no gangway connections possible at all. Presumably it was whatever the Eastfield foreman had to hand. I encountered it on the Springburn to Cumbernauld shuttle.

 

[Bletchleyite]

First North Western did did with some class 101s towards the end. They attached an extra power car to some of the power to the power+trailer sets. In other words, all three cars had a cab, rather like some of the current GWR class 158s.

Correct. Reason for doing that was that the power cars of the power-trailer sets all had van areas and none had toilets (or was it they all had toilets and no van?). Whereas the old power-trailer sets were increasingly struggling to keep time (and often conked out due to overheating on the hilly east Manchester locals - there was a watering can at Romiley for topping the coolant up if I recall!) so couldn't be used in that way alone. So the fix was to add another power car on the end, which was not used in service, effectively just as a locomotive. Only the two connected vehicles of the original power trailer set were unlocked.

 

[jupiter]

Part of the problem with driving trailers, apart from dragging the additional weight, is that they bring another couple of brake cylinders and associated vacuum pipework for your two exhausters on the power car to have to deal with. A single-cab power car often works quite sweetly by itself.

 

[edwin_m]

As it happens 15x DMUs can also run independently if necessary for shunting or whatever, it's only later builds where you got into things like only certain vehicles having compressors.

I don't think they'd be allowed out on the main line without some special arrangement, as they have to have a Track Circuit Actuator on the last bogie and they are only fitted to the ones under the cabs.

There's a story/myth I heard that once upon a time Tyseley managed to couple up some of its many and varied DMU cars so part of the formation had a cab each end but consisted entirely of trailers. This was scheduled to uncouple during the day and the powered part was duly driven away leaving the driver of the remainder wondering what to do...

 

[Bikeman78]

Correct. Reason for doing that was that the power cars of the power-trailer sets all had van areas and none had toilets (or was it they all had toilets and no van?). Whereas the old power-trailer sets were increasingly struggling to keep time (and often conked out due to overheating on the hilly east Manchester locals - there was a watering can at Romiley for topping the coolant up if I recall!) so couldn't be used in that way alone. So the fix was to add another power car on the end, which was not used in service, effectively just as a locomotive. Only the two connected vehicles of the original power trailer set were unlocked.

Yes, the power-trailers were DMBS+DTSL so the trailers had the toilets. The extra power cars came from other power-trailers that were disbanded. The 2001 stock book has 101654, 101656 and 101663 as three cars. I am not sure if there were any others. I think the extra cars were occasionally unlocked on busy trains, but I could have made that up. I travelled on 101656 from Manchester to Blackpool North in August 2000. I'm pretty sure it was a five car formation. The leading car was definitely open because I had the forward view for the whole journey. It's possible that the middle car was locked up but that would have been a pain.

 

[norbitonflyer]

There's a story/myth I heard that once upon a time Tyseley managed to couple up some of its many and varied DMU cars so part of the formation had a cab each end but consisted entirely of trailers. This was scheduled to uncouple during the day and the powered part was duly driven away leaving the driver of the remainder wondering what to do...

I heard a similar story, but the setting was Glasgow Central.

I have also heard of a manager at Woking requisitioning the rear four cars of a 12-car up service to be detached and form a shuttle to Alton to cover some problem on that route, against the protestations of some of the operating staff. Only after the rest of the train had left did it dawn on him that a 4TC can't move on its own - and it was now blocking the platform.

 

[Bikeman78]

I heard a similar story, but the setting was Glasgow Central.

I have also heard of a manager at Woking requisitioning the rear four cars of a 12-car up service to be detached and form a shuttle to Alton to cover some problem on that route, against the protestations of some of the operating staff. Only after the rest of the train had left did it dawn on him that a 4TC can't move on its own - and it was now blocking the platform.

Hilarious. The detachment must have been done from the west facing cab in the eight coach. Had they tried it from the cab in the ninth coach, the problem would have become apparent before it was too late.

 

[Bletchleyite]

Yes, the power-trailers were DMBS+DTSL so the trailers had the toilets. The extra power cars came from other power-trailers that were disbanded. The 2001 stock book has 101654, 101656 and 101663 as three cars. I am not sure if there were any others. I think the extra cars were occasionally unlocked on busy trains, but I could have made that up. I travelled on 101656 from Manchester to Blackpool North in August 2000. I'm pretty sure it was a five car formation. The leading car was definitely open because I had the forward view for the whole journey. It's possible that the middle car was locked up but that would have been a pain.

I never saw one open (and heard complaints and confusion about them not being) despite doing plenty of east Manchester 101 "bashing" around then, though that doesn't go to say that in what were much more relaxed times in terms of complying with the rules any traincrew didn't unlock it themselves when they saw things a bit busy.

Suspect it was indeed the middle of 5 that was locked. It wouldn't have been a pain as such because 101s aren't end gangwayed, so whatever the formation a double 101 formation wouldn't be walkable through in the middle.

 

[MadMac]

I heard a similar story, but the setting was Glasgow Central.

One I heard about from a long-retired BR Operations “higher up” from his days in the Burntisland Control Office dates from the early days of 1st gen DMUs: twin set limped into Dundee depot late at night, depot staff quickly determined that it was an issue that wasn’t going to be fixed overnight so they coupled up a spare car to the good one. Driver arrived in the morning to prepare his set, but found that no engines would start. You’ve probably guessed by now that they’d marshalled two driving trailers together. I did once see a Queen Street-Dundee service, normally at that time a 25 plus four Mark 1 coaches, made up from three 101 power cars.

On a side note, probably the last 1st gen power-trailer two car sets to operate in Scotland were a couple sent from Norwich following the 1984 Ayr depot fire: they were returned with thanks after a couple of months.

 

[Harpo]

When vacuum-braked van trains were very common and formed a network, there’d occasionally be single first generation DMU vehicles in their consists to transfer them to/from works.

 

[308165]

I never saw one open (and heard complaints and confusion about them not being) despite doing plenty of east Manchester 101 "bashing" around then, though that doesn't go to say that in what were much more relaxed times in terms of complying with the rules any traincrew didn't unlock it themselves when they saw things a bit busy.

Suspect it was indeed the middle of 5 that was locked. It wouldn't have been a pain as such because 101s aren't end gangwayed, so whatever the formation a double 101 formation wouldn't be walkable through in the middle.

I recall it happening, but only once. There had been some sort of issue with the overhead supply on the Glossop line so after a long gap in service a three car 101 was sent, this being late Saturday afternoon service the was very busy and the locked coach was opened. I stood in the van on the way to Glossop.

 

[Magdalia]

The Scottish Region had a surplus of 2-car units after the 1974 WCML electrification in Glasgow, so scrapped some of the driving trailers and used the power cars to add to other 2-car sets, giving two power cars out of three instead of one out of two. They were done indiscriminately by type, and it was not unusual to find sets from three different manufacturers.

Tyseley also did this when the Cross City Four Oaks-Longbridge service started.

When vacuum-braked van trains were very common and formed a network, there’d occasionally be single first generation DMU vehicles in their consists to transfer them to/from works.

I wasn't around to see it but I'm told this happened quite frequently on the 0555 Doncaster-Lincoln passenger train. This morphed into an ECS that arrived at Cambridge mid-morning, occasionally with ex works DMU cars on the rear.

 

[Merle Haggard]

When vacuum-braked van trains were very common and formed a network, there’d occasionally be single first generation DMU vehicles in their consists to transfer them to/from works.

Some d.m.u. were later prohibited from hauling tail loads - indicated by 'LW' stencilled on the ends - presumably because of poor structural strength between their drawbars. I recollect that the Regional or Sectional Appendices had marshalling instructions for conveying d.m.u. cars in e.c.s. trains, from what I recall had to be marshalled at the rear.

 

[norbitonflyer]

Some d.m.u. were later prohibited from hauling tail loads - indicated by 'LW' stencilled on the ends - presumably because of poor structural strength between their drawbars. I recollect that the Regional or Sectional Appendices had marshalling instructions for conveying d.m.u. cars in e.c.s. trains, from what I recall had to be marshalled at the rear.

I always assumed the LW stood for "lightweight" - that is, they were of light alloy construction - and would therefore distinguish between simiklar looking units such as class 108 (lightweight) and classes 107 or 114 (heavy weight). There were some routes, such as the Cumbrian Coast, where the latter were not supposed to go.

 

[Merle Haggard]

I always assumed the LW stood for "lightweight" - that is, they were of light alloy construction - and would therefore distinguish between simiklar looking units such as class 108 (lightweight) and classes 107 or 114 (heavy weight). There were some routes, such as the Cumbrian Coast, where the latter were not supposed to go.

Indeed, LW meant lightweight. I'm sure that the restriction on tail loads was in one of the Appendices and I'll try to find it later.
I have the distinct recollection that it was a 'panic' about 1968 - probably their unsuitability proved empirically - and there was a rapid scheme to brand the affected cars. The fact that it was using a stencil rather than sign written supports that proposition.

The 79xxx units (Derby and Met Cam) at Cambridge shed were the ones I particularly remember and the conveyance of tail loads had been common on branches in East Anglia to cut down on trip working. They generally didn't mix with heavyweights there.

When vacuum-braked van trains were very common and formed a network, there’d occasionally be single first generation DMU vehicles in their consists to transfer them to/from works.

Additional reply

In the L.M.R. General Appendix (1972 version) there is the following instruction regarding conveyance of d.m.. cars;

Not more than two lightweight vehicles may be conveyed 'dead' in a train and they must be placed together at the rear of the train. Lightweight vehicles are indicated by the letters 'LW' painted on the vehicle ends.

I always assumed the LW stood for "lightweight" - that is, they were of light alloy construction - and would therefore distinguish between simiklar looking units such as class 108 (lightweight) and classes 107 or 114 (heavy weight). There were some routes, such as the Cumbrian Coast, where the latter were not supposed to go.

Perhaps the reason was that the lightweight stock was 57' against the 64' 6" heavyweight stock. Somewhere there's a list of restrictions on routes for specific types of coaching stock, but I can't remember where it appears.

I have the recollection that Derby stuck to 57' to avoid changing jigs, a bit like they stuck to 8' + 8' 6" for coupled wheelbase from about 1872through to the 350 shunters