There is a very interesting discussion (for given values of interesting) on the RMWeb forum about BR Modernisation Plan diesels.
As any student of British motive power knows, the early years of the nationalised British Railways saw large-scale building of new steam locomotives, including a whole range of new standard designs. Then in the late 1950s there was a crash programme of dieselisation in an attempt to stem increasing financial losses, followed by a drastic rationalisation of the size of the network in the shape of the Beeching cuts. Both those newly-built stream locomotives and many of the early diesels were scrapped after ridiculously short lives. The epitome of this was D601 “Active” spending years sitting in Woodham’s scrapyard in Wales surrounded by the rusting steam locomotives it was built to replace. What a waste of resources.
What was to stop British Railways adopting the policy of West Germany? They had a far earlier end to steam locomotive building, accompanied by a rolling programme of electrification and what was initially a partial dieselisation. The first diesels replaced the oldest life-expired steam power, with the surviving newer steam engines concentrated on those routes eventually scheduled for electrification. West Germany saw thus a slower and more gradual elimination of steam over a period of 25 years rather than a decade. The last steam ran into the mid-1970s by which time the locomotives had reached the end of their economic lives.
The original 1955 modernisation plan envisaged a pilot scheme, whereby small numbers of locomotives would be ordered of a variety of different designs from different manufacturers, to be evaluated in traffic before placing large-scale repeat orders. That never happened. Such was the rush, perhaps motivated by a belief that government money must be spent now or it might not be available later, that BR placed repeat orders before they had time to complete any meaningful evaluation.
The least bad consequence was bulk orders of lumbering and obsolescent designs like the English Electric class 40, which at least had the advantage of working reliably. The worst was the ordering of more than a hundred Paxman-engined Clayton class 17s straight off the drawing board, which proved to be not fit for purpose.
The whole Type One saga is illuminating. The specification was for a single-cabbed locomotive with a power range of around 800hp to replace small tank locomotives on local freight working. The most mechanically reliable of the pilot scheme designs proved to be the English Electric class 20. But it was deemed unsuitable due to poor driver visibility when running hood-forward. What they wanted was a centre-cabbed locomotive in the vein of the German V100, but the combination of low hood and high cab proved impossible within the restrictive British loading gauge.
So they came up with centre-cabbed twin-engine design using railcar-style engines which became the ill-fated class 17. The reliability was so poor the whole lot went for scrap after a very short period and BR placed a repeat order for more class 20s. By the time those locomotives arrived, changing traffic patterns and Beeching’s branch line closures meant the original need for these low-power machines had evaporated. The 20s eventually found another niche working in pairs on coal traffic in the East Midlands, quite different work from that for which they were originally designed.
A lot of what went wrong was down to politics, both interference by government and internal within British Rail. There is the distinct impression that some business went to firms purely because they were based in areas with high unemployment. At the time each of British Rail’s regions had a lot of autonomy and all did their own thing. The Western Region famously chose diesel-hydraulic power rather than the electric transmissions preferred by everyone else, and got its own Pilot Scheme designs. The Southern Region rejected the Pilot Scheme altogether, came up with its own specification and ordered the class 33s from BRCW, which proved to be highly successful. One mystery was why there were no further orders of 33s for other regions, while Derby works were content to churn out vast numbers of underpowered class 25s.
It was the Type Two specification, double-cabbed locomotives in the 1100-1300 power range for secondary passenger and freight work which saw some of the real turkeys. You could even argue that the BRCW class 26 and 27s were the only unquestionably successful designs. The Metrovick Co-Bo class 28 suffered from the shockingly unreliable Crossley engines which had proved equally useless in the very similar A-class locomotives in Ireland. The class 21s demonstrated that North British, despite being one of the most successful steam locomotive builders, were nowhere near as adept at building diesels, a parallel with America’s Baldwin Locomotive Company. The class 23 “Baby Deltics” were English Electric’s one failure, needing complete rebuilds very early on. Even the numerous and eventually very long-lived Brush class 31s needed re-engining early in their lives after problems with the original Mirrlees power units.
At the end of the 1960s British Rail found themselves with a surplus of motive power following Beeching’s heavy pruning of the network, and made the sensible decision to reduce the number of types in service by eliminating the unsuccessful and unreliable designs. The decision to phase out the Western Region’s entire fleet of diesel hydraulics as non-standard remains controversial to this day, since some of the locomotives such as the Hymeks and Westerns acquitted themselves well in service and were built in significant numbers. But few would question the cull of Type One and Type Two designs; even when teething troubles had been eliminated and the locomotives could be made to work reliably, classes like the Baby Deltics were too few in number to make economic sense to keep.
We’re lucky some of those unsuccessful early designs survived to make it into preservation. One of the Metrovick Co-Bos, now under restoration in Bury, spent many years as a carriage heating unit, while one Clayton class 17 has a lengthy post-BR career as a works shunter at Ribble Cement. There were sadly a couple that frustratingly got away despite surviving into the diesel preservation era. Pioneer diesel-hydraulic D601 languished at Barry only to be scrapped as late as 1980, and Baby Deltic D5901 lingered in departmental use and was only scrapped in 1976.
But despite the obvious waste of resources, it does mean British railway modellers have a far wider array of different locomotives to model.