Posted by Howard Lewis on 24/10/2022 05:34:36:
Possibly some of the problems with early diesels stemmed from a lack of familiarity, so that applying steam locomotive techniques to a diesel engine and its transmission sometimes did more harm than good.
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Very likely, but also it was difficult to get diesel engines just right – their design, build and maintenance are all more demanding than other reciprocating types. Once a diesel engine is sorted it walks all over steam, but not until it's fully debugged. In comparison, steam engines are much more forgiving – lower temperatures, pressures, material requirements and tolerances. Apart from the boiler, when they go wrong, which is often, the causes are fairly obvious and straightforward to fix. However, despite their simplicity, steam locomotives spend most of the day doing some sort of maintenance rather than hauling traffic. Whilst hammer wielding engineers love 'em, accountants know steam locomotives are a big problem. They cost too much to run.
Germany was world leader in diesel engine technology for most of the 20th century. Other nations arrived late in the game and generally made engines that were either less efficient or less reliable. I suspect a tendency of firms and workers new to diesels to over-estimate their skills whilst under-estimating the technical difficulties, especially the need to get everything 'just right'. Possibly they made the mistake of believing all British engineers were competent diesel designers because Harry Ricardo made an important contribution to the breed. So firms employed relatively inexperienced designers, often under-invested in tooling and quality management, and struggled to train workers convinced 'the old ways are the best'.
Not only the UK had trouble making high-end diesel engines. In the US, the Hoover-Owens-Rentschler company were the world's most successful maker of Corliss Steam Engines. As demand for steam fell during the early 20th century the company moved into making industrial oil engines with moderate success; certainly not newcomers. Like British oil engines of the period their engines worked reasonably well, but were noticeably inferior to German engines. But the company were a fairly safe bet.
In the run up to WW2 HOR were contracted by the US Navy to develop a compact powerful diesel engine for submarines. To meet the requirement, HOR designed a double-acting diesel based on a successful German MAN engine. It was a disaster; in the US Navy the engines where known as 'whores' because of their extreme unreliability. The problem was two-fold: adding an extra cylinder to the German design unbalanced the engine causing severe vibration. The engine would probably have been 'good enough' except the Americans were unable – at the time – to make gears strong enough in the space available to run reliably without stripping teeth. As a result the engine had to be replaced by less efficient and powerful units. Far from ideal, but at least they didn't break down.
Submarine and railway diesels are similar – they both meet a need for a powerful reliable engine that fits into a confined space. The job was too hard for HOR, who had far more experience than some of the British companies who attempted to supply BR. Given time to debug their prototypes I'm sure the British companies would have got there in the end, but no chance of that; they had to get it right first time. I think Industry were unwise to try, but maybe the gamble would have paid off. A successful British diesel loco engine with development costs paid by the taxpayer, would have sold like hot-cakes around the world.
Then as Howard suggests, a mixed bunch delicate engines end up being maintained by chaps familiar with a cruder technology who don't see any need for a torque wrench…
Engineering is far more difficult than successfully making interesting stuff in a shed with a Myford!
Dave