Ah, great - I was wondering how I was going to go about scratchbuilding those. They're coded KFA, if that's any help? First four hits on Google brings up the following:
http://gingespotting.smugmug.com/Wagons/K-TOPSCode/KFA-CN/17174841_kmkPgM/1/1302098120#!i=1302102068&k=FtRgfZR
http://wrightys.smugmug.com/TavyWagons/KFA-Crane-Match-Wagon/23394802_GXfF9c/1889630004_V9XdSks#!i=1889630004&k=V9XdSks&lb=1&s=A
http://www.davekirwinphotography.co.uk/p402838757/h15756C8A#h15756c8a
http://www.davekirwinphotography.co.uk/p402838757/h1FAFCDF8#h1fafcdf8