A lost diesel loco

The Class 43 from NBL D833-D865 were to have originally been D605-D638 possibly part of the negative feeling against them was a heavy many axled beauty compared to the nippier, lightweight Swindon/German version. Swindon wanted more lightweights, and so NBL duly provided these instead. Swindon did rebuild some of the Power Units and the later ones were'nt so bad, but the NBL ones tended to be in 100000 miles less then the Swindon MAybachs. The NBL Voith transmission also suffered from quality issues, and allegedly engine oil was put in them on the Western Region. It is worth noting today that many units have similar built transmissions today. Including the Scottish 21s,and BLue Pullmans, the MAN engine ran almost 50million miles! Engine problems were almost endemic on BR including the Paxmans on 15s, 16s, 17s, Mirrlees Class 30s(later EE engined Class 31s) Crossley engined 28s and Sulzer engined Class 47s been the other horror stories. But trouble was had with Western and Warship Maybachs, Deltics, later 50s 58s and very lately the new 73/9s so puts it into perspective. Hence the plunge for GM 2 strokes with cast iron reliability. But we love em all us cranks!

 

My understanding is that the class was ordered on political grounds, given that in the early 1960s NBL was in financial trouble due to a lack of orders for steam locomotives, and the local MPs were pressing the Government to provide financial support; their solution was to award an order for the 5 locomotives BUT NBL made fatal errors in the production of them. Firstly it priced them too low on the assumption that it would get repeat orders where it could then increase the price and recoup the losses from the first order (its tender price of £86000 per loco compares with the production cost of £102,000 per loco). Secondly it built the locomotives based on 10000 / 1 (remembering that Derby had long used NBL as a sub-contractor to provide LMS Derby designs at short notice including the Royal Scots and Jubilees) as can be immediately noted on the bogies and the construction of the bodyshell. Thirdly the MAN engine drawings were supplied in metric measurements and errors were made in the conversion to UK measurements hence the initial engine problems.
Whilst the Government tried to help the financial situation by providing orders for the 5 "Warships" and 58 Class 21 and 58 Class 22 locomotives (the type 2s built to provide a direct comparison between electric (Class 21) and hydraulic (Class 22) transmissions) the reliability of the MAN engine proved fatal and NBL went into receivership in the early 1960s.
There has also been the suggestion that the order date for all 3 classes, which confirms the orders as part of the initial Pilot Scheme, was actually much earlier as the Government sought to provide assistance with suggestions that NBL was working on designs for the "Warship" locomotive as early as February 1955 with BTC approving the order on 25/01/1955, placing the order on 17/02/1955 and ratifying the order as part of the Pilot Scheme on 16/11/1955. Sadly my source for this information died before he could read some of the official company records - and I passed his NBL records onto the NRM in the 1980s when helping his girl friend to dispose of his railway files.

 

thanks for the info above, really interesting