More unique was the front end design, incorporating the drivers cab but retaining passenger access between units via a pullman gangway, particularly necessary to allow access to the griddle car from all coaches. The design was based on the front end of the Class 303 but with the gangway placed centrally and also incorporating a headcode box. Also notable was the curved wrap-around glass on the cab windows, but these proved expensive to replace and later an additional pillar was inserted so that flat glass could be used. The units were originally class AM9 (AC Multiple Unit) pre-TOPS, and were painted in the BR standard coaching stock maroon livery lined black & yellow, with the driving end gangway doors painted warning panel yellow.