The Metropolitan Railway H Class consisted of eight 4-4-4T steam locomotives, numbered 103 to 110. They were built by Kerr, Stuart & Co of Stoke on Trent in 1920 at a cost of £11,575 each. A "notable addition" to the Metropolitan Railway, these locomotives were purchased for the express passenger trains on the mainline between Harrow (later Rickmansworth)—the change point from electric locomotives—and Aylesbury or Verney Junction.