DP1 power unit in Class 55?

[Bobby B]

Hi

can anyone tell me if the Deltic DP1’s power unit was used in the 55’s with or without modifications, or any other Loco?

[Going Spare]

Looking at Wikipedia information, the production class 55 loco's used the same power unit as the Deltic DP1 prototype although six years separated their manufacture and as the engine manufacturer's type number is slightly different no doubt due to developments that occurred during that period and experience gained with the prototype loco in service, it is difficult to say whether the power units were precisely the same.

I do not know of any other rail use; I believe the engine was a marine power unit.

[Bobby B]

Thanks again GS. Most interesting

[81F]

The BR Class 23 "Baby Deltic" used a single smaller 9 cylinder version of the Diesel engine whereas the Class 55 used two larger 18 cylinder power plants otherwise nothing to add

[threelink]

I believe that the Deltic engine was based on the power unit used in RAF fast recovery vessels which was in turn, ironically, based on a German design.

[atom3624]

It was supposed to be a power unit for the fast coastal patrol boats I think.

Well covered with 'a quick Google'.

Al.

[Seacommander]

Brian Webb's book 'The Deltic Locomotives of British Rail' is very informative about the engines in DP1 and DP2/Class 55 which ultimately comprised the fleet of Deltic locomotives.

The engines were indeed developed from a marine version with the major difference between both applications being a much modified phasing gear casing to take the traction motor generator. Beyond that there were inumerable minor modifications to components such cylinder liners, pistons (bolt on crowns instead of screwed on crowns) connecting rods (polished or unpolished) etc. Such was the rate of engine failure (reaching a peak between Oct 1970 and May 1971 when 31 engines out of the 57 in the fleet were under repair!) and ever developing remedial work that it could be true to say that at any one time there were probably only a few wholly identical engines.

By 1963 when DP1 was withdrawn from service after covering 425,000 miles its engines were removed and added to the pool of Class 55 engines.

[Bobby B]

Thanks all for the info. Most informative