The open third/second exhibited the greatest variety in Mk1 design. The etch represents the type having a centre vestibule with doors on both sides, as well as end doors both sides. The vestibule divided the coach into two saloons of four bays each, one of which was divided into two to provide two non-smoking bays. Diagrams 89 and 93 had 2+2 seating with a centre gangway; diagram 94 had 2+1 seating with an offset gangway. A further 44 carriages identical to D94 but specifically for dining were classified as diagrams D60 and 61 (Comet Models B25).