Kelly was concerned about the AAR spec. metal so that is why I mentioned that lead could be added to the melt to achieve it. But I do agree that 660 has proven itself as a perfectly suitable bearing material in identical service in industry and should be satisfactory for this application.

Belmont Metals is a great source for bearing babbitt. Dont know what the full catalog entails, but it is extensive, and I imagine they can make anything you need.

We used them for an 8" babbitt armature bearing. I cant find the spec sheet as to what grade we got though.

Jason Lamb says there are hundreds of 5.5 x 10 and some other sizes at Kovalchik's Indiana, PA yard. Everett RR didn't even have to flycut them ...

Just make sure the backer is still in spec.

Your mileage may vary ...

You might check with the Durango & Silverton (disclosure: I just left after two seasons as a brakeman and fireman). All but one coach has plain bearings of various size, and they run enough miles that hotboxes are an occasional problem. Every train carries replacement brasses and the tools to jack up the car and replace one en route. If they don't make their own brasses, I'm sure they can point you to a supplier.