The original coaches were delivered in HST sets for Western Region (Class 253) with Trailer First (TF), Trailer Restaurant Unclassified Kitchen (TRUK), Trailer Second (TS), and Trailer Buffet Second (TRSB) cars in the formation TF-TF-TRUK-TS-TRSB-TS-TS. Complaints from guards about engine noise in the guards' compartments in the power cars led to the Trailer Guard Second (TGS) in 1980, based on the TS but with the end vestibule and one seating bay replaced by a guard's compartment. This replaced the last TS in all sets from 1980 onwards. Sets delivered for Eastern Region (Class 254) contained eight coaches, originally in the formation TF-TF-TRUK-TS-TS-TRSB-TS-TS. The TRUK cars were quickly replaced by a TS on the Western Region and most had been replaced on the Eastern Region by 1985 (many later rebuilt into loco-hauled buffet cars). TRUB cars (Trailer Restaurant Unclassified Buffet) were built from 1978 to replace the TRUK cars, and these were reclassified as TRFB (Trailer Restaurant First Buffet) from 1985 on the Eastern and London Midland Regions and from 1989/90 on the Western Region. The original interiors were fitted out fully carpeted with InterCity 70 seats. First Class had orange and red stripes on both carpet and seating, whilst Standard Class had a blue and green scheme. From May 1987 onwards, both HST and Mark 3 loco hauled sets were repainted and refurbished into the Intercity swallow livery.