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DHP1, meaning Diesel Hydraulic Prototype number 1, was a prototype Type 3 mainline diesel locomotive built in 1965 by Clayton to demonstrate their wares to British Railways. It was designed for mixed traffic work, being equipped with steam heating facilities for working passenger trains. It was painted red, with the cab area above bonnet-level height painted cream.
Visually similar to their Class 17 Type 1 product, though longer, it was similarly unsuccessful and was scrapped where it was built having done very little work, mainly for British Rail in a limited area around Derby.