This Sentinel locomotive was built in 1945 and delivered to Tottenham Gas Works in January 1946.  It received the number 11 and worked regularly until the early 1960s. Latterly it was retained as a spare to two diesel locos and was little used after 1965, being offically withdraawn in 1968.  In 1970 it was purchased for preservation by a Quainton member and moved to Quainton.

In this engine the drive passes via a two speed gear box through a single chain to the front axle. This is connected to the rear axle by another chain on the same side.  The maximum speed in high gear is 11 pgh, and in low gear 6˝mph, whilr the halage capacity on level track is in excess of 600tons.  The space between the boiler and the cylinders at the front of the engine is occupied by a 340 gallon water tank.

Restoration proceeded rapidly and No. 11 was steaming again by mid-1971. Later the loco was repainted in its original livery of dark red and black with yellow lining.