However, particularly in Scotland and the Southern Region, the situation was far less ideal, with large numbers of pre-grouping classes struggling to keep up with traffic.

The principal modifications to the Fairburn design involved the reduction of their envelope to enable them to fit into the L1 loading gauge.

The biggest mechanical change was a reduction in cylinder size, also to reduce cross-section, and a corresponding increase in boiler pressure to compensate.

The Standard 4 tanks were originally allocated to all regions of British Railways, bar the Western.

Older types were withdrawn in preference to the Standard 4s, whose class remained intact until 1964 (except for 80103 as noted below).

One Scottish Region example, 80002, remained in Glasgow past the end of steam haulage until 1969 as a static carriage heating boiler; eventually being preserved on the Keighley & Worth Valley Railway.

80097 has recently been steamed in preservation and entered service in March 2019 following its restoration from scrapyard condition at the East Lancashire Railway.

80002 operated over the former BR system in the 1970s when it appeared at an open weekend in Leeds arriving and returning home from the event under its own power.

In 1994, 80079 joined up with 80080 to work a number of steam specials including a run over the Cambrian Coast Line.

[citation needed] 80135 has been used on the Grosmont to Whitby workings for the North Yorkshire Moors Railway on the Esk Valley Line.

The difference is that she has water cannons on top of her tanks (for a role as a fictional fire engine) and a large brass bell.