The new carriages, have sleeker designs, larger windows and are in a bright red "reminiscent of the old London Underground pre-1960s livery". They'll form a substantial part of the DLR fleet throughout the London 2012 Games. Trains are being lengthened to three carriages to deal with growing passenger numbers from 2010.
However, as my colleague pointed out, the diagram Ken & co are carrying makes it look as though they are just moving from one car to two cars (ie 100% extra capacity). Surely it wouldn't have been difficult to have added an extra car to reflect the real three car situation?
If you'd like to see pictures of the trains actually running Ian has a post and some shots in his Flickr stream.