The Thumpers were diesel electric multiple units which were introduced by British Rail in 1957 for use on Southern Region non electrified lines. We start with footage dating from 1969 with units operating shortly prior to closure of the Swanage branch. Then we see operations from the mid 1980s of 6 car units working the line between Tonbridge, Tunbridge Wells and Hastings before it was electrified in May 1986. A jump to 1993 sees unit 1001 working in a 2 car formation on the Kent & East Sussex Railway. Further features include final days working on the East Grinstead and Uckfield line including a journey between Crowborough and Uckfield. Thumpers are then shown in scenes from 1998 and 2003 working between Ashford and Hastings.