Short Trains Beckton Tower Gateway

Having stayed in a hotel just off the Beckton branch at Christmas, I was a little surprised at times to find a 'short set' arriving rather than a full 3-unit train.

I indeed mean the short 2 car trains.

Or possibly just a bit of bad luck in the timing of run off the mill problems caused by the wear and tear of running an intensive service with increasingly unreliable, ageing fleet. Something has to give.
The Stratford-Canary Wharf service is only rarely not a two-car operation (I did see a three-car train between Christmas and New Year though, presumably fewer commuters and the start of the sales was the reasoning).
The Woolwich to Stratford International service has been operated by two-car trains every time I've used it in the past six months (although that is admittedly not that often).
Bank to Lewisham is the DLR's busiest route and really needs more capacity than the current three car trains can give.
Bank to Woolwich Arsenal is the second busiest route and really needs three car trains, at least in the peaks. When I was living there a few years ago 2-car trains at the weekend sometimes happened (especially when they were catching up on deferred maintenance post-Olympics) and they were busy but not overcrowded. With the new housing around Pontoon Dock this line is getting busier and busier.
Tower Gateway to Beckton is therefore the one that has to give as the least used of the routes on which three-car trains operate. Certainly it used to be the case that UEL and ExCeL meant that the traffic profile on that branch was more spread out and less peaky than the Woolwich route. If that's still the case then two car trains will cope better than might be expected if you just look at daily total ridership figures.

It doesn't feel like that long since the Beckton service was run with just a single vehicle. Shows how much development there has been in the Royal Docks area in a fairly short space of time.

Just stumbled across this on the DLR section of the TfL web page:


 
I wonder what component has been causing the fleet so much trouble?

That was my first thought. The DLR uses a different wheel profile to both LU and mainline stock that is better suited for the tight radius corners but poorer at high speed (hence the hunting on the fast sections, particularly through the tunnel to Woolwich), so just borrowing a lathe from somewhere else might not be easy. Although having said that I have no idea how configurable for different profiles wheel lathes are.
Even if they are using a lathe elsewhere, detaching, shipping and reattaching wheels/wheelsets/bogies is going to be more time consuming than reprofiling in situ.

Chiltern Rail's lathe at the Aylesbury depot is completely in-situ - the carriage is just shunted across it and both wheels are done at the same time. You can see the swarf (trimmings) being pushed along a channel by Archimedes screw to the hopper outside. As it will be completely NC (numerical controlled), the only thing to dictate profile is what the operator requests.

I don't know about all services, but certainly most were. However, this was only possible for a short time and there was a significant maintenance backlog afterwards with many services that were routinely 3 cars being only 2 (e.g. off-peak Bank-Woolwich trains). The need to account for this was one of the reasons for the length of time between the Olympics and Paralympics (although of course far from the only reason). I think it was about 2 months after the Paralympics finished before I next saw a three-car train to Woolwich at the weekend.

That'll be because of the broken bit of kit. When I last used it regularly, the normal pattern at weekends was for Bank trains to be 3 cars and Stratford International trains to be 2 cars.

Stratford branch trains used to be a mix of 3 and 2 car services, but running at a lower frequency. When the concession changed hands a couple of years back, the timetable was changed to run 2-car trains at roughly twice the frequency, which has actually made a positive difference to capacity.

not that I'm aware of

The S stocks are walk through and they do suffer that problem to an extent, tut it's not as bad as it could be. Bank actually has three exits from the platform - one slightly aft of the second door of the train (north end), one about level with the third last and one between the two, and the corridor it leads to has four exits - the north end escalators are the busiest leading to the Bank exits, the lift exit, central line, W&C and the north exit of the Northern line platforms. The second exit is the lift to the same locations so is very much the quietest, even though its the only step-free route. The south end escalators lead to the sub-surface lines and Monument exit and there is a side exit to the south end of the Northern line platforms (which is also best for the eastbound SSR platform, but I've only used this in the opposite direction). The only stations I can think of with exits right at one end of the train only are Shadwell, Mudchute, London City Airport and Stratford high level, so on most journeys people do spread out anyway.

Yes the flexibility of multiple units per train is useful, but the capacity increase will outweigh those benefits. The coupling and uncoupling doesn't come for free, as the couplers on the current units are wearing out, and all the added equipment means there is more to go wrong.

Quite a few others do, off the top of my head there's at least Poplar, Beckton, Prince Regent and All Saints.

In a group I'm a member of on Facebook someone has posted a photo of a DLR unit on the back of a lorry with the caption "Beckton to Ilford. Another successful move." although I think the photo was taken at Beckton rather than Ilford.
I don't know whether the following image will work, but if it does credit goes to Alex Whitehouse: