A total of 31 Class 91s were built between 1988 and 1991 for high-speed express passenger train haulage as part of the East Coast electrification programme of the late 1980s. Also known as InterCity 225s in anticipation of their service speed of 225km/h (140mph), they were also referred to as ‘Electras’ by BR during their development phase.No. 93031 was the last locomotive to be built at Crewe Works and, as a result, earned its place in preservation and is currently on display at the Museum of Scottish Railways.