Sunday, 30 December 2007

ALRC Locomotive No 1: Thunderbox

Bob Brett who was the founder and owner of the Little Melton Light Railway (LMLR) commissioned David King of Suffield to build a locomotive. It was completed in February 1989 and the locomotive was given the name Thunderbox because of the hole in the seat. It was the first locomotive to trundle through Melton Wood Junction when the LMLR was opened on 22 April 1989.

It is powered by a Honda CD 200 motor cycle engine which drives an Eaton 6/7 hydrostatic unit (combined hydraulic pump and motor) via a chain from the gearbox. The output shaft of the unit is fitted with a sprocket driving a chain to the rear axle of the front bogie. This in turn drives the front axle of the bogie by a separate chain. The engine, hydraulic unit and bogie form a completely self contained assembly attached to the locomotive only by the bogie pivot. The rear bogie is free running and is fitted with parking brake acting on all four wheels. The all timber body is made of sweet chestnut. Because of the untimely death of Bob Brett the LMLR closed on March the 24th 2002 after almost fifteen years of operation.

On the 12 October 2002, Thunderbox was bought and transferred to the ALR. It was given the number 1 because it was the first locomotive owned by the Railway. It was kept under cover in the engine shed until the summer of 2004 awaiting the necessary manpower to restore it to full working order. Work began by overhauling the fuel system and on the 29 June the engine ran properly for the first time since arriving on the ALR, albeit using a 12v battery for the starter motor and a separate 6v one for the ignition.

Since then the electrical system has been completely up-graded to 12v, although the starter motor is still the original 6V model. A 70AH battery is now housed in a compartment at the rear of the loco; this compartment also contains a key operated isolation switch in the positive lead so that the electrical system is effectively dead when the key is removed.

Thunderbox is unique with a style of its own; you either like it or loathe it. Although one or two of the ALRC members who initially disliked its appearance, have since had a change of heart. 0n our first anniversary open day held in July 2004 we were visited by the Chief Mechanical Engineer of the Bure Valley Railway, David Phillips, in his case it was love at first sight.