Power Units
At the heart of a Class 50 is a 16CSVT power unit built by English Electric. This is a development of the unit found in English Electric Class 40 diesels which in turn can trace its origins back to those that powered the two pioneer London, Midland and Scottish Railway (LMS) diesel-electric locomotives (numbers 10000 and 10001) back in 1947.
The unit is a medium-speed, 16-cylinder four-stroke, direct injection engine developing 2,700bhp at its maximum speed of 850rpm. The cylinders have a 10 inch diameter and a 12 inch stroke. They are arranged in a V-formation, with the twin banks of cylinders driving a common crankshaft. For each set of four cylinders there is a separate turbocharger and charge cooler.
The sheer size of the unit can be seen in relation to the chair in the foreground of this photograph. Power unit serial number IH6937 was originally fitted to D410 from new in 1968. It is currently undergoing a complete rebuild and overhaul ready for its fitment back into 50026 Indomitable. This unit is believed to be that which was salvaged from 50025 Invincible following its untimely end in August 1989 when it was involved in a high-speed derailment at West Ealing.
Class 50s
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