This locomotive was built by W G Bagnall in 1937 and was designed to be only 90inch high. The reduction in size by dropping the cab floor down between the main frames. The 24 foot 9inch inches wheels were set just 5 feet apart which allowed it to negotiate the sharp curve by Par Moors drier. The outside cylinders allowed it to be serviced without the use of an inspection pit, and Bagnall-Price valve gear was fitted. The locomotive cost £1,200 and weighed 16 long tons on delivery.
It is one of a number of locomotives that operated at the Port of Par on the Cornish coast which was used by English China Clays. The locomotives had to be squat in stature as they had to run underneath a low bridge which carried the Penzance to London main line.
It had originally been planned to name the locomotice Chough after a distinctive Cornish bird. The message was received by Bagnall’s as Cough, which they thought was rather strange and so it was sent to Par without a nameplate. The Judy nameplates were fixed in 1960.
For the post war years Judy shifted the clay single handily, but as the traffic increased the need for a second engine was shown, Judy was paired with Alfred in 1953. Over the years the two engines worked in many liveries, depending on the several different operating companies of their time and the colour of cheap paint available. Many different shades of green were used and found on the engines, varying from a Southern Malachite Green to a darker Brunswick Green. The two engines have a valve gear that was of Narrow Gauge origin. The two engines worked tirelessly for many years, with the usual crew daily, and most of the maintenance being done in house. In 1969 Judy was withdrawn from service as the cost of boiler repairs could not be justified considering how little rail traffic was now handled at Par. It was kept in the engine shed until 1978 when it was moved to the china clay museum at Wheal Martyn near St Austell where she was displayed as a static exhibit alongside a locomotive from the Lee Moor Tramway in Devon.
In 1978 when Alfred left, Judy was pulled out for a final photo shoot together, or so it seemed. After leaving the docks, Judy was given to the China Clay Museum at Wheal Martyn. Here it stayed for many years until November 2002, when due to reorganisation of Wheal Martyn, Judy was handed over to the Cornish Steam Locomotive Preservation Society. Judy was returned to its work mate at the Bodmin & Wenford Railway. Alfred was in steam for the occasion, on hand to shunt the new arrival across to the steam shed.
In 2004 she was given to the care of the Cornish Steam Locomotive Preservation Society (CSLPS). Before Judy could be moved from Wheal Martyn to their base at Bodmin General railway station a specialist had to remove the asbestos insulation around the boiler. A £50,000 grant was made from the Heritage Lottery Fund towards its restoration, and the work was supported by both Poltair Community School and the Cornwall Young Archaeologists Club. Part of the firebox had to be renewed, this being the reason it was taken out of service at Par in 1969. One of the four axle journals were found to have suffered water damage while on static display, but otherwise it was in reasonable condition despite not having been in steam for more than 30 years. Heavy and specialised repairs were undertaken by contractors, but much of the work was done at Bodmin by volunteers.
The boiler was steamed in June 2008 and it moved under its own power in October 2008 for the first time in nearly 40 years. Now fitted with a vacuum brake so that it could operate passenger trains, Judy entered service on the Bodmin and Wenford Railway in April 2009.
After an overhaul the locomotive re-entered service on the Bodmin & Wenford Railway in November 2022.