Standard Open
Second Open or Standard Open is a British coach designation for open-saloon second class coaches with 2+1 abreast seating, usually seating 48 passengers. Second class coaches with more conventional 2+2 abreast seating were designated Tourist Standard Open seating 64 passengers.
There were a number of variations. The majority were built using the same body shell as the Mark 1 SK and TSO. When production started, these were classified as third class. There were also 15 "true" second-class coaches, also known as "Boat Seconds" as they were used on boat trains for continental destinations. These rare vehicles had an interior layout to almost first-class standards with 2+1 seating and a central door without vestibule. When the European railways agreed in 1956 to abolish third class, British Railways simply reclassified third-class vehicles as second class except for the special "Boat Seconds" which after some deliberation were finally reclassified as first class carriages in 1959. There was also a one-off experimental 39-seat SO built by BRCW as part of the Mark 1 new prototype scheme. In 1965 the new Mark 2 designs incorporated a small run of just 28 Mark 2a SO carriages.