Piers Connor latest article in Underground News focuses on LU's R stock,
which was planned just after the end of WWII, and first entered service
in 1950. The stock was partly made up of Q38 stock trailers, which were
converted to driving motor cars, with new-build R47 NDM cars.

Piers notes that a full 8-car R stock train cost about £100k at the
time, which he estimates as £2.7m in today's money. I wonder how that
compares with the cost of a new S Stock train? And what does the
presumably much higher cost of modern, high-tech trains deliver?

The R stock was comfortable, had electric sliding doors, and all cars
were motored. The later batches had aluminium bodies, just like modern
trains. Unlike the S stock, it wasn't air-conditioned, and didn't have
open gangways, but did allow either 6 or 8 car operation with uncoupling
(so trains could run as 8-car in the peaks, and 6-car off-peak).

I don't know if the S stock has higher performance or is safer than the
R stock, but I doubt that it's more comfortable. So how much real
progress has there been in the 60 years since the R stock was developed
in the austere post-war period?