Jay is an 0-4-0 diesel hydraulic, she was the third locomotive to be completed by the Kirklees Light Railway and was outshopped from Clayton West in 1992. She is the railways workhorse and can quite often be seen up the line with the works train in tow. When originally built Jay was powered by a Dorman 2 cylinder diesel engine. Interestingly the power unit was originally fitted to one of the Blackpool Pleasure Beach locomotives built by Davy Paxman in 1947. The loco is now in her third livery, originally being outshopped in brown, she was later painted into yellow livery with wasp stripes on the buffer beams before being painted into her current livery of black with red frames and buffer beams.

During the winter of 2002 Jay was rebuilt in the railways workshops. The worn Dorman 2 cylinder engine was replaced by a Ford 4D with a 4.15 litre capacity although she still retains the original hydraulic drive unit which was used in a loco at Blackpool Pleasure. Jay has been outshopped with vertical bonnet sides and running boards and also received a new dashboard and air sanders. It is hoped that eventually a wider cab may be fitted to accomodate a bench seat suitable for two people. To see a comparison of Jay before and after her rebuild click here.