T-Series

A T-series a built for the National Coal Board (UK).

The T-Series was a diesel-hydraulic type and was similar in appearance to the U-Series but was heavier and larger in most respects including the wheel diameter (21-in on U-Series, 24-in on T-Series). Although it was designed with use as a mining loco in mind, none were actually bought for underground use. They were mostly sold for export with only two British customers, these being the National Coal Board, who used the type on the surface as stockyard shunters on 2-ft 6-in gauge systems at Allerton Bywater and Hem Heath Collieries, and Associated Portland Cement Ltd., who used one at their Kilvington Gypsum works.

During its production, the T was offered with three varieties of engine: the Dorman 6DA (air-cooled), the Deutz F6L912 (air-cooled) and the Perkins 6.354 (water-cooled). Transmission was by means of a Twin Disc 400 series torque converter coupled to a drop box, right angle gearbox and chain drive to both axles. Alternatively, a hydrostatic transmission was available, fitted with a Dowty "Dowmatic" variable displacement (swashplate) hydraulic pump, as fitted to the U-Series hydrostatics, this being connected to a Staffa motor driving by chains to the wheels. 

The T-Series was available in weights from 9 to 14 Short Tons. The additional weight was achieved by varying numbers of steel slabs that were mounted on the front and rear of the frame. Many locos were fitted with air brakes in addition to a hand-wheel operated parking brake.  

Number Series (built between 1972 and 1984)

100T 001-003, 008-015.

101T 018-023.

102T 004-007, 016.

103T 017.