Hi John,
Firstly - I am assuming that the axles are running in coned bearings or the castings are coned and the bogies are nice and square.
I had a similar problem when I bought a couple of Hornby Thompson suburban stock - we had tons of them around Fife and although I built some in plasticard years ago I could not fault the Hornby examples - one of the attractions was the fineness of detail on the bogies. When I managed to get them home after being on holiday I began to realise there was no easy way to get the wheels out to convert to scalefour without breaking anything. There was space to put S4 wheels in and the 00 ones ran true.
Like any number of other modellers, we have many diesels running on our layouts all of which have uncompensated wheels and they run well. Also when I make any track I test it all with some uncompensated stock - so the track is pretty good. My solution was to use one of my grinding tools and cut the underside of the axle boxes to take out the axle ends and remove the 00 wheels. I was simple then to drop in the S4 wheel sets and I did not try to remake the axle boxes I simply made covers using black plasticard and painted them up. They run beautifully and have run on a number of other layouts without any problems.
The carriages of course are commercially made and have been well engineered, but if your bogies sit well on a sheet of glass or mirror and there is no discernable rock and roll then they should be OK - could I suggest you try at least one bogie this way and see what the ride is like. A few minutes with a grinding tool will give you a quick answer.

- Here we have the underside with little to see to be honest. the delicacy of the footboards etc. is evident. The coaches are still to be weathered before being used on the Buckhaven /Methil branch on my new Wemyss layout.

- From normal viewing there is no sign of any work having been done. Since your wagons are made of metal then I would probably have used thin brass or nickel silver and glue.
Hope that is of some help John, I know I may get some flack when there is so much springing etc around, but you are looking for solutions and this has worked for me.
Allan
