They were initially numbered 15500–15569, but from 1934 were renumbered 1–70. After nationalisation in 1948 British Railways added 40000 on to their numbers to number them 40001–70.
Numbers
Lot Number
Date built
Original
LMS 1934
BR
15500–20
1–21
40001–21
21
1930
15521–49
22–50
40022–50
29
1931
15550–69
51–70
40051–70
20
1932
Variations
Numbers 15520–39 (later 21–40 and 40021–40) were fitted with condensing apparatus to work around London. Some of the non-condensing ones were fitted with vacuum operated pull and push control.
Withdrawal
All were withdrawn between 1959 and 1962. None were preserved.