Lines 5, 6, and a section of line 2 which use 4 car sets.

Some trains on line 8 use 7 car sets.

In 1932 additional cars were purchased to increase the London fleet to 25 three car sets.

They were designed to run in two or three car sets.

By the mid-1930s they only ran in one or two car sets.

Up to five single cars can be operated together as a multiple car set.

All 35 four car sets were delivered by October 2005.

In January 1946 approval was given for the construction of 10 two car sets.

However since August 2009, 2 car sets have become a regular sight.

X21 is the other original series, and built as ten two car sets, with a less powerful motor.