There are as a lot of variation in wagons voor transportation of goods.
Most kits can be used in different era's as most survived the grouping to the big 4 in 1923.
The big four are:
Great Western Railway (GWR)
London, Midland and Schottish Railway (LMS)
London and North Eastern Railway (LNER)
Southern Railway (SR)
A couple also survived the nationalisation in 1948 into British British Railways.