Large Scale Central

Looking for

I am looking for long (or longer than the usual short 2 axle) flat car as used in England or on the continent in the first 40 years of the 20th century. It will probably be a 4 axle car(2 trucks). If I can get the plans I can build my own. I can also use long Euro or British gondolas or box cars with 4 axles. Any condition.
I can also use broken models for parts and to kit-bash my own in 1/32, 1/29, 1/24, 1/22.5, etc.
Thanks,
Stephen.