British Rail Class 52 - Performance

Performance

The highest recorded speed with a Western that O. S. Nock was aware of was 102 mph when D1068 hauled 9 coaches (305 tons gross) down 1 in 1320 (i.e. virtually level) at Southall. The train averaged exactly 100 mph for 12.8 miles between Slough and Ealing whilst hauling a service from Reading to Paddington.

However, when it came to drawbar horsepower the Westerns were less capable than the equivalent diesel electric locos. Nock states "whilst the Westerns took their rightful place as fast and powerful locomotives it became evident that they were showing the same deficiency in actual power put forth at the drawbar as the Warships had done. The highest output that came to my notice was a sustained 85 mph hauling 560 tons descending 1 in 1320, which equates to 1500 edhp (equivalent drawbar horsepower)". This is 56% of power at the flywheel, whereas for a diesel electric one would normally expect a figure of 75 to 80%. A similar result was obtained when Clough & Beckett compared the performance of type 4 diesel locomotives (Classes 45/46/47/50/52) hauling trains up the ascent to Whiteball summit. They deliberately chose data to show each class in their best light and included a Western run which produced 1775 edhp but they still concluded that "without doubt the Westerns get the wooden spoon certainly not what one would expect from units of 2700 bhp". The best performer was the Class 50, a 2700 hp diesel electric locomotive, on one run this achieved 2115 edhp.