In message . com, MIG
writes
The report in the previous link implies that is was made of two three-
car sets, ie six altogether.

The story (and also some other accounts I've read) suggests that a
number of people were standing, although that could be a case of "I'll
have an uncomfortable journey to save a few yards at the terminus".
As I remember my time on the Northern Line, trains were composed of four
and three car sets, each three car set being composed of only one
driving car and a panel driven (30000unit?) Now as all the driving
cars were either "A" or "D" end and as the units were uniform it would
suggest that all the 30000 units were either "A" or "D", I suspect "A".
At that time, only "A" and "D" units could couple under normal
circumstances. This is why I suspect press reports about six car
trains. As I've said I suspect the trains were only four cars long and
this came from seeing them in 16 foot tunnels and eight car platforms,
but if you can provide me with more accurate information, I'll happily
apologise and back down.
--
Clive.