The Paxman Valenta, also known as Y3J and RP200, is a diesel fuelled internal combustion engine formerly made by Paxman in Colchester, England. It was originally developed for, and previously used in the British Rail (BR) Class 43 diesel-electric locomotives, a pair of which powered the InterCity 125 High Speed Train (HST) in a push-pull train set configuration. The Valenta has also been used for electricity generation in diesel generators on offshore oil rig platforms in British waters. It is still in use in various marine applications today, such as the Upholder / Victoria class submarines, and additionally to provide the electrical power to propel and operate the Royal Navy's Type 23 frigates. The Valenta marine range was available brake powers ranging from 695 to 3655 kW rated to ISO 3046.

History

Locomotive use

The Paxman Valenta was developed in the early 1970s for British Rail (BR) with the aim of using in both freight and passenger locomotives. The engine was used in 1972 in the two pre-production Class 41, and 197 production Class 43 power-cars that were delivered to power HSTs between 1975 and 1982. In June 1973, the Valenta powered HST prototypes achieved a world speed record for diesel traction engines, reaching 143.2 mph. This world speed record was beaten in 1987 by a Valenta powered production HST, this time reaching 148 mph. The engine as originally fitted to the HSTs was designated 12RP200L, and was a V12 four-stroke diesel engine with direct injection unit injectors, turbocharger and air-cooled intercooler. It had a displacement of 78.96 litre, which developed 2250 bhp at 1,500 revolutions per minute. The design of the Valenta was based on the Ventura which was fitted to the Class 29 diesel locomotives, amongst others. The engine is famous for the 'Valenta Scream' on starting from rest, a distinctive high-pitched whine caused by the engine's turbocharger. In 1977, the Valenta received the Queen's Awards for Enterprise. In 1985, four power-cars (43167-43170) were fitted with Mirrlees MB190 engines. Beginning in 1995, a small number were fitted with Paxman VP185 engines, however the majority retained Valentas. In May 2005, First Great Western had Brush Traction fit two with MTU 16V4000 R41 engines, these V16 units which use common rail fuel injection are ultimately capable of developing 2,720 kW, though they are de-rated in the Class 43 HSTs to match the performance of the original Paxman engine. Judged a success, no doubt due to improved fuel economy, as part of a project to extend the lives of the HSTs, First Great Western decided to re-power its entire fleet. Great North Eastern Railway (GNER), CrossCountry, Network Rail, and Grand Central also decided to re-power their fleets with MTUs. The only operator not to was East Midlands Trains, which opted to replace its Valentas with Paxman VP185s. Grand Central's 43084 and 43123 were the last two Valenta-engined power-cars in service. They were taken out of traffic on 22 December 2010 for re-powering with the latter named Valenta 1972-2010.

Restoration

In May 2011, it was announced that the 125 Group would return prototype HST powercar 41001 to service. The power-car was at that time on static display at the National Railway Museum (NRM) in York, England. It received a full overhaul, and was fitted with a reconditioned Paxman Valenta RP200L engine, number S508 installed new into Virgin CrossCountry's 43153 in 2001, before re-installation into First Great Western's 43143 after a spell in storage. It was one of about 10 engines that the 125 Group obtained. On 15 November 2014, 41001 hauled its first passenger train in preservation.

Australian XPT

The engine was also fitted to the State Rail Authority's New South Wales XPT, or Express Passenger Train, which was based on the HST power car design. Fifteen power car units were built in the 1980s by Commonwealth Engineering, Sydney, supplied with twenty Paxman Valenta engines rated at 2,000 bhp. This was followed by four additional power cars (using four Paxman supplied Valenta engines) by ABB Transportation, Melbourne in 1994. All were re-powered with VP185s in the early 2000s.

Usage