One locomotive, No. 37395, was modified changing it from coal to oil-fired in 2002, another has been modified and the Railway is looking to retro-fit further locomotives to oil-firing. Conversion of coal into oil-fired system has the potential to reduce the danger of forest fires that could be caused by embers flying out from the locomotive. Additionally, the effort involved in the manual lifting of coal and putting it into the boiler is eliminated. The current oil-fired locomotives need only one fireman to accompany the driver, while coal-fired engines need two firemen. However, X 37395 was reconverted to coal-burner in August 2009 for unknown reasons. Four new oil-fired steam locomotives have been ordered to replace or ease the load on the existing X class locomotives. They too will be of basically the same design as the existing locomotives and are also described as being of the X Class. The first...
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of these, No. X 37396, arrived in Feb 2011, and entered service on March 24, 2011. The second oil fired steam engine, No. X 37397, with a welded boiler used for the first time, was rolled out at Golden Rock in Feb. 2012, and should have entered service on NMR in March 2012.
Courtesy: Wiki