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Famaz00
Hey guys I'm thinking about getting a 4-6-4 or something of the that size for my layout that has a radius of 9 3/4 and wanted to know if that works
Without some modifications to the engine, that may be challenging. Bachmann lists minimum radii for its current N scale steamers and all are 11¼” or larger. While some of them might be coaxed around 9¾” curves, the 4-wheel leading and trailing truck versions might be especially finicky. The only real way to know for sure on your trackwork would be to try it – as long as you can return the engine for a refund if it doesn't work.
Some older models may get down to 9-10" radii. There was an old ConCor 4-6-4 that was reputed to go around 9" radii in a Model Railroader review. But that's porbably very close to the limit.
Finding a way to broaden the curves would be a big help in terms of appearance and performance.
I have neither N scale steamers nor curves that sharp to test, but others may have more direct experience to share.
Good luck with your layout.
Byron
Edit: I just remembered and re-read an MR (4/96) review for the excellent KATO Mikado (2-8-2), which also claimed a minimum radius of 9". So it may be possible, depending on the quality of your trackwork.