John B wrote:

I also thought the 172s were going to be fairly conventional 2+2 wide-
aisle train layout, rather than longitudinally seated like the 378s -
is that wrong too? Otherwise, I'm struggling to see how they'd have
much more nominal capacity than the 150s. Are there any pictures/mock-
ups of the LO 172s available?

I'm sure that has been the understanding in the past, particularly because
the LO 172s were always intended to be passed on elsewhere relatively soon
(in railway terms of course). IIRC they were also always going to be leased
from one of the mainstream Roscos for that reason, rather than owned by TfL.
(Although that subsequently changed and a new Rosco emerged for the
dedicated LO stock).

Paul