GWR Haigh Foundry locomotives

GWR Snake and Viper
South Devon Railway Exe and Teign

Type and origin Power type Steam Builder Haigh Foundry Serial number 25–26 Build date 1838 Total produced 2

Specifications Configuration 2-2-2 2-2-2T (after rebuild) Gauge 7 ft (2,134 mm) Leading dia 3 ft 5 in (1,041 mm) Driver diameter 6 ft 4 in (1,930 mm) 6 ft 0 in (1,829 mm) (after rebuild) Trailing dia 3 ft 5 in (1,041 mm) Wheelbase 13 ft 0 in (3.96 m) Cylinder size 14.75 in × 18 in (375 mm × 457 mm) 13 in × 18 in (330 mm × 457 mm) (first rebuild) 15 in × 18 in (381 mm × 457 mm) (second rebuild)

Career Operators Great Western Railway South Devon Railway Number in class 2 Withdrawn 1868-1869 Disposition Unknown, probably scrapped

The first 19 locomotives ordered by Isambard Kingdom Brunel for the Great Western Railway included two unusual Haigh Foundry locomotives.

Snake and Viper were built at the Haigh Foundry in 1838 with 14.75-by-18-inch (375 mm × 457 mm) cylinders and the driving wheels geared 2:3 in order to keep the cylinder stroke speed low while allowing high track speed, in line with Brunel's specifications. Within a couple of years they had been rebuilt with 13 in × 18 in (330 mm × 457 mm) and conventional drive. They were later converted to 2-2-2T tank locomotives, possibly when they were sent to work the South Devon Railway, and at some time fitted with 6 ft 0 in (1,829 mm) driving wheels and 15 in × 18 in (381 mm × 457 mm) cylinders.

Names

• Snake (Haigh Foundry 25; 1838–1869)

Between 1846 and 1851 it carried a different name, Exe, while working on the South Devon Railway, after the River Exe; it reverted to Snake when it returned to the Great Western Railway.

• Viper (Haigh Foundry 26; 1838–1868)

Between 1846 and 1851 it carried a different name, Teign, while working on the South Devon Railway, after the River Teign; it reverted to Viper when it returned to the Great Western Railway.