North British Locomotive Company - Diesel Locomotives

Diesel Locomotives

Whilst highly successful as designers and builders of steam locomotives for both its domestic market and abroad, North British failed to make the jump to diesel locomotive production. It did build a Paxman engined diesel locomotive, British Rail 10800, originally ordered for the London, Midland and Scottish Railway before the 1948 nationalisation of British Railways, but not delivered until 1950. Another Paxman engined locomotive was PVH1, built in 1953 as 'Paxman Voith Hydraulic 1' (hence the identity) for the Emu Bay Railway, Tasmania, and survives today preserved at the Derwent Valley Railway (Tasmania). Its wheel formation is -D- being a hydraulic transmission locomotive, so in appearance it looks like an 0-8-0. It also built 8 Paxman engined shunters British Rail Class D2/1. Later in the 1950s it signed a deal with the German company MAN to construct further diesel engines under licence. These power units appeared in the late 1950s' British Railways (BR) designs pre-TOPS British Rail Class D3/1 (later D3/4), and later designated Class 21, Class 22, Class 41, Class 43 (Warship) and Class 251 (Blue Pullman) None of these were particularly successful: constructional shortcomings with the MAN engines made them far less reliable than German-built examples. A typical example of this was the grade of steel used for exhaust manifolds in the Class 43s - frequent manifold failures led to loss of turbocharger drive gas pressure and hence loss of power. More importantly, the driving cabs of the locomotives would fill with poisonous exhaust fumes. BR returned many North British diesel locomotives to their builder for repair under warranty and they also insisted on a three-month guarantee on all repairs (a requirement not levied on its own workshops).