Gas guzzlers

While diesel power became the standard for replacing steam, gas turbine technology was briefly considered as a potential alternative – with Britain’s first such prototype arriving 70 years ago in early 1950.

THE gas-turbine story, in terms of locomotive applications, was started by the Swiss FederalRailway in a search for suitable motive power for routes with low traffic density where electrification could not be justified.

A prototype ordered in 1939 proved to be reliable in traffic and thus attracted interest from the Great Western Railway, which resulted in a visit to the manufacturer Brown Boveri by the GWR’s chief mechanical engineer, F W Hawksworth, in 1946.

This was a period when improved steam engine design was continuing, with new types of locomotive being produced by all of the ‘Big Four’ companies. But the proposal for a GWR ‘Pacific’ had not been progressed, which resulted in alternative options being considered to provide higher power.

The advantage offered by gas turbine technology was a consistent output of at least 2500hp, which was more than could be offered by diesel power at the time. The LMS, for example, developed two diesel-electric prototypes in partnership with English Electric, Nos. 10000 and 10001, but accepted their individual rating of 1600hp was some way short of the power that could be produced by a Coronation Class ‘Pacific’ steam loco. The idea was the ‘twins’ would operate in multiple if the power output demanded this.

Like the LMS prototypes, the GWR opted for two locomotives but each with sufficient power output to operate independently on trains that needed greater haulage capability than steam traction could provide.

The decision was that the locomotives would be supplied by different manufacturers, one from Brown Boveri and the other from Metropolitan Vickers in Manchester. Both companies were expected to produce equipment that offered an output of 2500hp, and contracts were signed with the GWR in June 1946.