Although these coaches were in production for a relatively short period they came to be as much recognised as were the earlier Gresley designs. They had steel flush sides, straight roof, an internal arrangement whereby no passenger had to walk past more than two compartments to reach an exit door, but in a reversion to earlier practice on this and other railways, no cross vestibules at the ends of the coach. The graceful oval windows were distinctive.
The coaches entered service on premier routes on the LNER. Interchanging of stock in Scotland led to them being found on the West Coast main line also.
There were many other carriages built to this diagram, but they are not easily represented by this etch. Some had pressure ventilation and fairings over the solebars for the Flying Scotsman and Junior Scotsman sets. Carriages built from 1949 onwards had round cornered windows as it was found that the square corners gave rise to corrosion.