The class were highly successful in service, with only three failing to complete one million miles (1,600,000 km) during their lifetime.

[1] The engines were commonly seen across the entire North British Railway network, and were the second largest class of tank engines on the railway, after the NBR A class.

On the NBR they were numbered in a sequence commencing with 795 (and are sometimes referenced as 795 class engines).

A total of 40 locomotives were built, all but one of which came into British Railways (BR) ownership at nationalisation in 1948.

Hornby have produced a basic model in OO gauge since 1983, though in recent years[when?]