The 26 Bristol and Exeter Railway 4-4-0ST locomotives were broad gauge 4-4-0ST steam locomotives. They first entered service in 1855 and the last was withdrawn in 1892. The Bristol and Exeter Railway was amalgamated into the Great Western Railway on 1 January 1876.
The locomotives were built in four batches, each by a different builder, with variations between them, noticeably in the size of the saddle tank.
Five locomotives built by Rothwell and Company with 1,100-imperial-gallon (5,000 L; 1,300 US gal) gallon saddle tanks and 18-foot-4-inch (5.59 m) wheelbase.
Four locomotives built by Beyer Peacock with 1,280-imperial-gallon (5,800 L; 1,540 US gal) saddle tanks and 19-foot-5+1⁄2-inch (5.931 m) wheelbase.
Ten locomotives built by the Vulcan Foundry with 1,280-imperial-gallon (5,800 L; 1,540 US gal) saddle tanks and 19-foot-5+1⁄2-inch (5.931 m) wheelbase, the same as the Beyer, Peacock locomotives built five years earlier.
Six locomotives built by the Avonside Engine Company with 1,440-imperial-gallon (6,500 L; 1,730 US gal) saddle tanks and 18-foot-4-inch (5.59 m) wheelbase.
No. 2051 was withdrawn following a fatal collision at Norton Fitzwarren railway station in Somerset while working a special ocean mail train from Plymouth on 11 November 1890.