On Sep 22, 8:58 pm, "Clive." wrote:
In message ,
Colin Rosenstiel writesThe Northern main line had 7 car trains, with M-T-T-M four car units

This is definitely wrong. Each four car set comprised a driving motor,
a non-driving motor, a trailer double compressor and a driving motor
car. Your setup implies only four motor cars per train, but there were
definitely five. I don't know where your info comes from, but I worked
on them and I know I'm right.
--
Clive.



That is true; the four-car units definitely had NDMs. The Northern
and Bakerloo had seven-car trains which were nearly all DM-T-NDM-DM +
DM-T-DM, in fact all were by the early to mid 1970s, which I can
remember properly. The UNDMs had all gone, and were relatively rare
in the first place. I don't know when the last one ran.

The UNDMs were all from the extra build known as 1949 stock, rather
than 1938 stock as such. I think that 1949 stock consisted of only
UNDMs and trailers and allowed units to be reformed.

time passes

I've just found another source suggesting that the Northern City line
only had three-car units, and that six-car formations ran from the
opening of the Victoria Line in 1968, which fits with the report.
Presumably traffic increased with people changing and Highbury and
Islington.

Also that the last UNDMs were withdrawn in 1974, as were the last
converted 1927 coaches that had been formed into 1938 stock.