On many latter day steam locomotives, when roller bearings were first introduced, it was common for many locomotives to use a mix of bearing types as the railroads experimented with roller bearings.
For example, many locomotives in the early roller bearing era only had roller bearings on the driving wheels and continued to use plain (friction) bearings on the idler (lead and trailing truck/bogie) wheels. In many other cases, all wheels and axles were fitted with roller bearings but the side and main rods still had plain bearings.
I had this idea of specifying different bearing types for each mechanical component. So instead of:
ORTSBearingType ( Roller )
It would be something like this:
ORTSDriveWheelBearingType ( Roller ) ORTSIdlerWheelBearingType ( Roller ) ORTSRodBearingType ( Friction )
Or if we want to get even more detailed and advanced:
ORTSDriveWheelBearingType ( Roller ) ORTSIdlerWheelBearingType ( Roller ) ORTSSideRodCrankpinBearingType ( Roller ) ORTSSideRodKnucklePinBearingType ( Friction ) ORTSMainRodCrankpinBearingType ( Roller ) ORTSMainRodWristPinBearingType ( Roller ) ORTSValveGearPinBearingType ( Friction )
...obviously that last example is a little too extreme but you get my point, right? What do you think?