Seventy-four Class 439s passed into British Railways ownership in 1948 and they were numbered 55159-55236 (with gaps).

The 19 and 92 Classes were originally fitted with condensing apparatus for use on Glasgow Central Low Level lines.

In 1922 Pickersgill introduced the 431 Class with larger cylinders and a cast-iron front buffer beam for banking.

This was possibly to move the centre of gravity forwards and put more weight on the driving wheels.

In 1925 the LMS introduced their own version of the 439 Class and these were numbered 55260–55269 by British Railways.