Standard Open

British Rail Standard Open
British Rail Standard Open
	A Mk1 SO at the Midland Railway - Butterley in 2006
In service	1963–
Manufacturer	BR Derby (C&W), Eastleigh, York Works and Birmingham Railway Carriage and Wagon Company
Number built	Mark 1: 111,; Mark 2: 28
Capacity	48 Second
Operators	British Rail
Specifications
Car length	64 ft 6 in (19.66 m)
Width	9 ft 3 in (2.82 m)
Height	12 ft 9+1⁄2 in (3.90 m)
Maximum speed	BR1: 90 mph (145 km/h),; B4: 100 mph (161 km/h)
Weight	32–33 tonnes (31–32 long tons; 35–36 short tons)
Bogies	BR1 or B4

Second Open or Standard Open (coded SO) is a British coach designation for open-plan second class (later standard 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 (TSO).

There were a number of variations. The majority (95) 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 (which were still three-class even after the June 1956 abolition of railway Third class). They seated the same number, but the centre vestible was absent, and the centre doors opened into a seating bay. One 39-seat SO was built by BRCW as part of the Mark 1 new prototype scheme. There were also 28 Mark 2 SO carriages built.

Interior detail of a Mk2a SO.

See also