Peckett OQ Class

Peckett OQ Class
Peckett OQ Class 0-6-0ST No. 2150 Mardy Monster at the Elsecar Heritage Railway
Type and origin Power type Steam Builder Peckett & Sons Serial number 2124, 2150–2151 Model OQ Build date 1951–1954 Total produced 3
Specifications Configuration: ​  • Whyte 0-6-0ST Gauge 4 ft 8+1⁄2 in (1,435 mm) Driver dia. 4 ft 0+1⁄2 in (1.232 m) Loco weight 55 tons Fuel type Coal Firebox: ​  • Grate area 19.1 sq ft (1.77 m2) Boiler pressure 200 psi (1.38 MPa) Heating surface 921 sq ft (85.6 m2) Cylinders Two, outside Cylinder size 18 in × 26 in (457 mm × 660 mm)
Performance figures Tractive effort 29,527 lbf (131.34 kN)
Career Operators Mardy Colliery Tower Colliery Disposition 2 scrapped, 1 preserved

The Peckett OQ Class is a class of 0-6-0ST steam locomotives built in Bristol, England by Peckett & Sons. Three were built; no. 2124 for Tower Colliery in 1951 and nos. 2150 and 2151 for Mardy Colliery in 1954. No. 2150 has been preserved and is named Mardy Monster. According to Heritage Railway magazine it is "Britain’s most powerful industrial locomotive". This claim may be misleading because it is based on tractive effort rather than horsepower.^{[1][2][3][self-published source]}

After being withdrawn in 1976, No. 2150 was preserved by the Swanage Railway in 1979. In 1997 it was purchased by the Elsecar Heritage Railway, returning to service in June 2003. It was withdrawn after its boiler certificate expired in 2013.^[4] Its overhaul was never completed and it was sold in 2020.^[5]

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