The railcar pictured in post 33 is a good representation of one of the Great Western Railcars introduced in 1933.
In the early 1950's these cars ran as pairs (sometimes with an extra carriage between them on services from Cardiff to Moor Street. They were very regular in their timing and you could, at that time, set your watch (almost) by their arrival. I know one sped along the North Warwickshire line, non stop, through most of the stations south of Hall Green around 8.20 - 8.30 am. They also ran out from Snow Hill to Stourbrdge.