The Only Living Boy in New Cross writes
Or, failing that, it'd be pretty easy to extend the Canada Water
platforms to take in the Rotherhithe ones, as they're so close; that'd
solve the problem of Canada Water not being able to take longer trains.

The ELL has 4-car trains at the moment. I presume they fit Canada Water
station. How much room is to 'spare' on the platform.

The proposals are for the extended ELL to be served by 4-car trains.
According to Tubeprune [1] each car on the A stock trains currently used
on the ELL is almost 16.2m long - so a 4-car train is almost 65m long.
AIUI, each car on a Networker train is 20m long, so a 4-car train would
be 80m long.

If Networker trains are to be used on the extended ELL, then the
platforms at Canada Water need to be about 15m longer than a current ELL
train. I don't travel on that line, but for anyone that does - perhaps
they could have a look at tell us. Are the platforms longer than the
trains? If so, does it look like the platforms are long enough to fit
another carriage of the same length? Because if you can fit 5 carriages
of the current length, then you'll be able to fit a 4-car Networker
train in.


Another possibility; even if the platforms aren't long enough. If
you've ever travelled on the Tyne & Wear Metro, the platform end walls
are false. The platform continues out of sight to allow for future
expansion - you only notice this if you look carefully when a train
approaches the station. Perhaps Canada Water was built in the same way?


[1] http://www.trainweb.org/tubeprune/Dimensions.htm
--
Dave