Standard Peat-haulage Locomotive
The standard peat-haulage locomotive is a diesel-mechanical 0-4-0.The engine is an automotive 6-cylinder which drives a 3-speed power shift transmission through a torque converter.
The final drive is by over slung worm gears on each axle; the gearboxes are shaft-mounted and restrained by rubber-bushed torque reaction links to the mainframe. Suspension is by bonded rubber “chevron” springs on each axle-box. Sanding gear is fitted to aid adhesion; the sand is gravity-fed but dispensed using pneumatically operated sanding valves.
The service brake is a spring-set air-operated caliper working on a ventilated disc which is mounted on an extension of the propeller shaft to the cab-end axle gearbox. Since the axles are coupled through the transmission output shaft by means of cardan shafts, the brake effectively operates on all four locomotive wheels. The maximum brake force is 22,613 lbs (100.6 kN) measured at the wheel rim. An emergency mechanical handbrake is also fitted.
Brake force is limited by adhesion; under wet conditions it is reduced to 3,969 lbs (1,800 kg), assuming the coefficient of friction μ = 0.15. Assuming a rolling resistance factor of 0.005, this gives a calculated braking distance from 25 kph with a loaded train (152,000 kg) on a level track of 146 m. This increases to 208 m on a 1 in 200 down gradient, which is the maximum permissible gradient.
The buffers are box-beams at either end, and the draw-gear consists of hooks and coupling chains.
Locomotive Specification: Overall width : 1,722 mm
Overall length : 4,419 mm
Overall height : 2,605 mm (over rail head)
Wheel diameter : 710 mm
Weight : 12,000 kg
Max. power : 115 bhp at 2200 rpm
Max. speed : 25 kph
Max. tractive effort : 4,800 kg