As I understand it, before 1956, there were 3 classes on British trains: 1st, 2nd & 3rd. Not all trains had all classes, & by the 1950s it had long been the case that the vast majority of trains had 1st & 3rd classes, but not 2nd. In 1956, 2nd & 3rd classes were merged, & in 1987 it was renamed...