The traction engine that featured as The Iron Maiden was a John Fowler & Co. 7nhp showman's road locomotive (works no. 15657, reg no. FX 6661). She was built in September 1920 as a class R3 road locomotive for heavy haulage work and saw many years' service on the Isle of Portland, hauling blocks of stone from the quarries to the harbour.
She returned to Fowler's works for conversion into a showman's engine, which entailed the addition of a dynamo bracket in front of the chimney, and a full-length canopy, among other things. Once converted she was based in Alfreton, Derbyshire and undertook fairground work, until bought for preservation in 1952. From new she was named Kitchener – until the film The Iron Maiden was made, whereupon she was renamed The Iron Maiden.
