Bevan Price
Established Member
- Joined
- 22 Apr 2010
- Messages
- 7,384
On the diesel side 47s and 50s are really second generation designs, coming along some years later than the original Type 4 (i.e. 2000HP +) designs of Classes 40 and 44/45/46, 56s were even later.
The power capability of the later designs was simply not possible prior to about 1962 and neither operators or politicians were prepared to wait that long. It might have been possible to get GM locos, but (according to an explanation I've seen from someone who was involved at a fairly high level) GM were insisting on all production being in the USA and payment being in US$ hard cash. The UK was in a fairly parlous state for foreign exchange at the time and the Treasury would not permit such a transaction.
Much of the multiplication of classes came from updated power units coming along (e.g. Cl 26/27) but some came from UK manufacturers who wanted a showcase for their products and managed to convince the politicians that BR should provide same, despite the objections of the engineers.In general the latter group were the less successful designs.
Yes, I think there was almost certainly some "political" interference to ensure diesel orders went to a range of loco. builders.