This locomotive was built in 1941 by Motor Rail Ltd of Bedford, works number 8703. It is one of that Company's 20/28 horsepower class of machine. It was supplied to Sir Alfred McAlpine and Co. on 31st December 1941 for use on construction work related to the war effort.
At some stage, it became the property of the Yorkshire, Ouse and Hull River Authority. When this Authority became the Yorkshire Water Authority, No. 36 was repainted from its original green livery to the present two-tone blue.
The locomotive was used on temporary railways laid to strengthen river banks and construct flood embankments. In 1980, the YWA stopped using railways for this type of work. As a result, No. 36 was purchased by the Welsh Highland Railway in December of that year.
Since moving to North Wales, it has been named Cnicht , after the local mountain of that name. It was the main shunting and maintenance locomotive for a while, but more recently the 60 hp Simplex locomotives (especially Jonathan and Katherine) have assumed this role.