Input (grade 12): Subsequent builds, which are subclassed as 168\/1 and 168\/2, were constructed at the same time as the Class 170 Turbostar and thus are part of the Turbostar family of trains.
Output (grade 12): Subsequent builds, classified 168\/1 and 168\/2, were given the newer style cab and a new design of wiring and thus are part of the Turbostar family of trains.