The MTH cars were railmotor trailers that were rebuilt from older Harris suburban sets (hence the H in the class name). There cars were rebuilt with an electric generator mounted underneath the car to provide power for lighting and other passenger comforts. They lost their center set of doors and were completely rebuilt on the inside. Their main use was behind DRC railcars and were regularly used on the stony point line. In later years, long after the DRC's were removed from service they were seen as one or two cars pulled by and A class locomotive on the Stony Point line passenger services. All cars have been stored since the introduction of sprinter services on the Stony point services in 2008. In 2011 MTH102 was outshopped in Metro livery and reclassed IEV102. Modifications recieved was much seating was stripped and the car was fitted with track recording equipment hence the classing IEV (Infrastructure Evaluation Vehicle). It can now be seen all over the electrofied suburban network pulled by normally push/pull T class's. The MTH cars are about the only example of the trailers outliving the railmotors themselves.