"Paul Corfield" wrote

There is a real fallacy in building assets that will last for over 100
years for about 10 years worth of projected demand. People complain
about the scale of somewhere like Canary Wharf JLE station but it can
handle huge numbers of people very effectively - it's in complete
contrast to somewhere like Victoria or Kings Cross which jam up or else
send people round corridors for 10 miles to spread the passenger load
out.

Or do what was done with the DLR, the ever-expanding railway, and design it
so that it can be expanded. Easier to do with a surface railway than
underground, though at least they built Bank long enough for 3-unit trains,
and even then they're now having to use SDO (at the 2nd Island Gardens
station and Elverson Road), and announce a train (from Bank) as 'all
stations to Lewisham, and then, as it's passing West India Quay on the new
spur advise that it won't stop there.

Perhaps what's needed is not building for 10 years and throw hands up in
horror when demand overwhelms capacity, nor build for what might be needed
in 30 years, but to build for 10 years with passive provision for expansion
so that increased capacity can be provided affordably.

Peter
(memories of a DLR fleet of 11 units, with manual PIS which could be rotated
to display destinations of Island Gardens, Tower Gateway, Stratford, or
Poplar)