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 eight Paxman engined shunters British Rail Class D2/1. In the late 1950s North British 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 and Class 43 (Warship). 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). Electric locomotives In the early 1950s, The General Electric Company (GEC) won a contract to build 40 electric locomotives for the South African Railways (SAR Class 4E) – NBL receiving the sub-contract to manufacture the locomotives with GEC-supplied electrical components. GEC and NBL co-operated again in the construction of early 25 kV AC electric locomotives for the West Coast Main Line (WCML) electrification project of the early 1960s. GEC won a contract for ten locomotives and sub-contracted the mechanical design and construction to NBL: Class AL4 E3036–E3045 (later Class 84 84001–84010) entered traffic in 1960–61. As with its diesel locomotives, the class suffered poor reliability and spent long periods out of service. A partial reprieve came when money was made available to extend the electrification of the WCML north to Glasgow but no immediate funds were available for more electric locomotives. The Class 84s were refurbished in 1972 and pressed back into service, being finally withdrawn between 1978 and 1980 following delivery of Class 87 locomotives. Decline In 1959, GEC, Clydesdale Bank and HM Treasury invested in a restructuring programme at North British to enable the transition of the company from steam to diesel-electric and electric locomotive manufacture,