S. G. Allsopp describes some of the problems experienced at diesel depots in the winter months.
British railways and the weather have fought constant battles ever since railways were invented. The weather usually wins. Sunshine buckles rails; snow clogs points and, if of the ‘wrong’ type, damages electrical equipment; obscures signals; and in cold weather everything freezes. Despite the experience with the LMS and SR designed prototype main line diesel locomotives and growing fleets of diesel multiple units and diesel shunting locomotives, little consideration was given to frost protection on the Pilot Scheme diesel locomotives or on those produced immediately afterwards.
The DMUs and diesel shunting locomotives used ethylene glycol antifreeze in their engine cooling systems. This anti-freeze solution has searching properties, finding weak spots and marking them with a white encrustation. Once initial problems with leaking flange joints and flexible hoses had been brought under control (they have never been completely cured) and with corrosion of light alloy components due to weak anti-freeze/water mixtures, the anti-freeze was left in the cooling systems all year round. As it also contained a corrosion inhibitor this was not a bad idea and much better than the treatment meted out to the mainline locomotives.
At first they used raw water straight from the tap in many areas, although the Eastern and North Eastern Regions used soluble oil in many of their locomotives. There were problems not only with rubber seals and hoses perishing but also with the pollution of water courses with this coolant. Eventually, because of severe corrosion problems, a mixture of water, borax and sodium metasilicate was used (successfully) as a corrosion inhibitor. Anti-freeze was not used in mainline locomotives until the introduction of Class 56 and the HSTs. As the engine cooling system of a Class 45 contains 360 gallons, the reluctance to use antifreeze is understandable!
Cooling systems
The design of engine cooling systems varies considerably. The English Electric locomotives suffered from several problems, Class 40 being under cooled and Classes 37 and 50 being over cooled! Early photographs of Class 40s taken in the summer often show the inward opening engine room access door open to let a little more air in. Unfortunately, as their radiator cooling fan was engine driven, when the engine overheated and engine revs had to be reduced, t
