Engine preheaters

Many of you may have seen a Class 50 start up during cold conditions and will have noticed the white smoke, flashes along with louds pops and bangs. Whilst this may provide some entertainment to the casual observer, it is not doing the engine any good. The smoke and noise are caused by the elements within the engine, such as pistons rings, which are cold and not yet expanded to the optimal size to enable a smooth running and good diesel combustion. To stop this happening and increase the engine life preheaters have been fitted to warm the coolant that circulates the engine. This in turn warms the pistons, rings and valve gear so that when the start button is pressed the engine starts and runs cleanly more quickly. An electric powered preheater was previously fitted to 50035, but this can be problematic and requires supervision as it tends to shut down prematurely. It also required a significant supply of electricity, which is not necessarily available on Heritage Railways and even on the mainline network. 50007 and 50049 are shortly to be fitted with diesel fired preheaters, so they can operate anywhere.