You would be better off with the Williams No. 5001 PRR K4 Postwar 4-6-2, it is a much more reliable engine.
Also, Weaver had a version of the the Prewar 5000 style K4 that used the same tooling from Samhongsa.
I sold my 5000 but still have the other two I just mentioned and am happy with them.
Hope this helps.
Ed Boyle