In 1946 English Electric decided to build a gas turbine mechanical prototype locomotive and by the time GT3 was finally completed in 1962, it had been rendered obsolete by the advances in diesel electric traction. In the end she only ran 17,000 miles in tests.
Tim Coles’ model is powered by an MW 54 turboprop engine built from a kit from Wren Turbines, Rotherham. The main shaft rotates at up to 175,000 rpm and idles at 40,000 rpm. The engine is started on gas and switches over to burn paraffin once the combustor is hot.
On the track, the locomotive has been occasionally temperamental, not unreasonable for such complex engineering. The automatic start sequence takes about 30 seconds and once the turboshaft is running, the locomotive drives much like an electric loco, Tim just has to turn up the power control potentiometer knob and away she goes. The power is then adjusted as required to tackle the up or down grades. On shut down, the engine goes over to automatic cooling with the starter motor.
While the turboshaft can run up to 175,000 rpm, such speeds are not necessary and the locomotive has a limited top speed to 120,000 rpm. In practice, it rarely goes over 100,000 rpm with an exhaust gas temperature of 450 degrees C. which is good for bearing life. The noise at idle is not great. At high power settings it is quite significant, but not to the level of requiring ear defenders. It produces quite a lot of hot exhaust gas, but presents no greater hazard than a steam loco. The exhaust is quite clear, no blue or black smoke, just heat haze. Fuel consumption is quite high at around 100 ml per minute and the loco carries 9 litres.
The loco was a major attraction at a recent exhibition running on 2km of the famous ‘Sinsheim’ track. To see the GT3 running was a memorable experience. As well as being impressive to see and hear Tim did quite a lot of research on the colour scheme originally painted chocolate brown. The green at the front and back of the engine and tender are correct on the model, as is the yellow lining.
