DLR 3-car trains a fundamental mistake

[Deleted]

Having a few minutes to spare here due to the weather, let's stir up a bit of a hornets' nest.

Ordering the new DLR trains was an expensive mistake. Instead they should have just ordered new centre sections for the existing trains, extending them from articulated to double articulated. Two of these together would achieve the same overall length as a 3-car train, at significantly less cost.

Just plain centre sections, only one extra bogie, no driving controls, etc. My guess is that you could get this for less than half the cost of the equivalent new trains. This approach has been done by several systems across Europe, the trains already have adequate power to handle it.

Furthermore, there would be no need for any of the space-wasting additional provision of yet more wheelchair areas, already grossly overprovided and underused on the existing fleet. The new centre sections could instead be configured PROPERLY, with what the DLR passengers really want, namely SEATS. I would guess that if fully seated you could get maybe 60 seats, fully face-to-back or face-to-face, into such a centre section, doubling the current provision and providing far more seating per train than the 3-car plan does. Standing and wheelchair areas would continue as now in the end sections.

Any thoughts? Did someone just want new Choo-Choos to play with rather than an effective and sensible spending of money?

[rincew1nd]

*sharp intake of breath*

Hmmmm, seems a good idea on the face of it, though no doubt there were/are reasons; I can think of:

• If a set is shortened because a unit is unavailable, it's halved in length rather than just loosing a third.
  
• Clearances with the centre section (?)
  
• Need to take units out of service for insertion[of the centre car].

I fully expect to be shot out of the water now, but I do *like* the idea of a centre car, aftter all it did take me a little while to realised that the "3 Car Project" was actually a '3 train project' though...

[norbitonflyer]

Are there some routes which are (or were at some time) intended to remain as two-car? If you converted to triple-artics you would need to keep some twins for these routes (or run them with trains of just one (tri-art) unit.

[andypurk]

Jan 6, 2010 23:28:25 GMT norbitonflyer said:

Are there some routes which are (or were at some time) intended to remain as two-car? If you converted to triple-artics you would need to keep some twins for these routes (or run them with trains of just one (tri-art) unit.

At least the Beckton route was originally going to remain a two-car route.

Other considerations include the complexity of adding a new section to just some of the existing units (in the original plan with just 24 new units). Remember that there are 95 of the B90/B92/B2K units and 55 new units have been ordered in batches of 24 and 31, so you would need to build a few more complete three section units (5 if the numbers are exactly the same) to keep the same total number of sections that we will have.

The original units were already quite highly utilised, so adding extra sections would have been quite slow with maybe only one or two units being spare at a time and the conversion would be quite a bit more complex than just inserting an extra car (as done with the 1996 stock on the Jubilee line) . Any 3 section units would then not be able to be used in 2 unit formations once they had been converted, so conversion would probably have to have waited until the all the stations had been modified. In the meantime, the Woolwich extension has opened which needs at least four more units.

[100andthirty]

A three car train is 50% heavier than a two car train. in order to maintain the performance, it would need to have 50% more power. However the lengthening is achieved, this is always true.
The existing trains propulsion system could not deliver the extra power

the articulated bogies on DLR trains are not powered so I see no way of delivering the extra power if the proposed lengthening were to take place.

Also the existing trains are between a thrid and a half way though their lives. Adding to these with new section would just bring more problems in 10-15 years time.

Adding to existing trains like this almost always costs a lot more than can ever be imagined and at best you get stuck with the underlying technology that is probably obsolete or obsolescent.

[Deleted]

Jan 6, 2010 23:28:25 GMT norbitonflyer said:

Are there some routes which are (or were at some time) intended to remain as two-car?

Only the Bank-Lewisham route is to be 3 car. All other routes will remain being served by 2 car trains.

[Bighat]

Jan 7, 2010 20:57:53 GMT @docklands said:

Jan 6, 2010 23:28:25 GMT norbitonflyer said:

Are there some routes which are (or were at some time) intended to remain as two-car?

Only the Bank-Lewisham route is to be 3 car. All other routes will remain being served by 2 car trains.

Err...........if that were the case, why has EVERY station on the system been lengthened to accomodate three car sets, including South Quay which was completely MOVED so that the new structure could accept THREE car sets?

[superteacher]

Jan 7, 2010 20:57:53 GMT @docklands said:

Jan 6, 2010 23:28:25 GMT norbitonflyer said:

Are there some routes which are (or were at some time) intended to remain as two-car?

Only the Bank-Lewisham route is to be 3 car. All other routes will remain being served by 2 car trains.

Incorrect - the whole of the DLR is being upgraded to 3 car working. They will begin the Beckton branch upgrade nexr year.

[Deleted]

Jan 7, 2010 23:31:31 GMT superteacher said:

Jan 7, 2010 20:57:53 GMT @docklands said:

Only the Bank-Lewisham route is to be 3 car. All other routes will remain being served by 2 car trains.

Incorrect - the whole of the DLR is being upgraded to 3 car working. They will begin the Beckton branch upgrade nexr year.

I didn't say that it wasn't. The whole of the DLR is being upgraded to be "3 car ready", but DLR only have plans to run 3 car trains on the Bank-Lewisham route.

To quote DLR: pressroom.dlr.co.uk/pdf/lightnews/Light_News_Autumn_2009.pdf

Longer trains will come into service on the busy Bank-Lewisham route, starting in the first half of the new year. They will be introduced on other routes according to passenger demand.

[astock5000]

Another reason not to extend the B90/B92/B2K units is that the oldest units are about 19 years old. I have no idea how long they will last, but even lengthening them only cost half as much as buying the B2007s did, it wouldn't save money because the center cars would only last half as long (at most) as the B2007s will.

Jan 8, 2010 9:07:54 GMT @docklands said:

The whole of the DLR is being upgraded to be "3 car ready", but DLR only have plans to run 3 car trains on the Bank-Lewisham route.

To quote DLR: pressroom.dlr.co.uk/pdf/lightnews/Light_News_Autumn_2009.pdf

Longer trains will come into service on the busy Bank-Lewisham route, starting in the first half of the new year. They will be introduced on other routes according to passenger demand.

That might explain why only 55 B2007s were ordered. The new stock would only make two extra trains if all trains were 3-car, and that is not enough for the Stratford International extension.

[mikebuzz]

Maybe most of the B90/B92/B2K units will be sold on to another network somewhere?

[Deleted]

Looking to the future, could the next generation of rolling stock be fixed units as long as a current three car set, with passengers able to walk all the way through?
If there are not enough B07s currently ordered to run a 3-car service on all lines, new trains will be needed soon, and once all lines are 3-car there would be no infrastructure compatibility issues.
I think they would have to be in eight segments to avoid increasing the wheelbase, which would also mean keeping the same number of bogies, thus avoiding any axle-load issues. Removing the gaps between vehicles and four sets of front ends and their associated controls would increase capacity, and reduce required maintenance.

[Chris M]

But reduce flexibility.
I don't know if it is in the plans or not, but while the Bank-Lewisham route needs 3-car sets during the week, does it need them on Sundays? If not then two car units could be run with the current setup but not with single length units.

Obviously there are advantages and disadvantages to both, but the DLR is a railway that appears to have been designed around flexibility, e.g. the signalling is fully bidirectional, and so the ability to retain that flexibility might be a more important factor than it was in the case of the S stock.

[Deleted]

Jan 16, 2010 0:30:17 GMT Chris M said:

But reduce flexibility.
I don't know if it is in the plans or not, but while the Bank-Lewisham route needs 3-car sets during the week, does it need them on Sundays? If not then two car units could be run with the current setup but not with single length units.

My opinion is 3 car trains are needed on Sundays too. Bank bound, you often you have to push onto a train at Canary Wharf and God help any families with buggies as they really struggle in a manner that must be quite distressing.