The British Rail Class 166 Networker Turbo is a fleet of diesel-hydraulic multiple unit passenger trains, built by ABB Transportation at their Holgate Road Works in York between 1992 and 1993. They were specified by and built for British Rail, the state-owned railway operator in Great Britain at the time.
The trains were designed as a faster, air-conditioned variant of the Class 165 Turbo, intended for longer-distance services, and, like the 165s, belong to the Networker family of trains.