[pschlik]

Update: I decided to dig into the Fcalc 2 documentation to see what its intended use case is for the low torque bearings. As I understand now, the low torque option is intended to represent modern roller bearings that showed up around 1990 with the introduction of the 286,000 pound load limit. This means I've actually been underusing the low torque setting, as it would be appropriate for modern freight equipment as well as modern passenger equipment. I'll be setting up my cars with a 286,000 pound load limit to use low torque settings instead of regular rollers. As for grease, I get the impression that's meant for train cars so old I don't have any of them in my install.

With the somewhat recent adjustments to the built-in starting friction calculations, I've been tempted to give my setup a good once over in terms of my davis numbers, going back to using the 'proper' implementation of friction rather than manually defined starting friction. Needing to manually calculate starting friction has been more trouble than its worth and just slows me down, so I'm taking this chance to simplify my installation and refine it simultaneously.

However, despite the constant talking about friction, I never really understood all the nuances of the bearing type parameter and which bearing type was most appropriate to use for which situations. Most of my work has just involved educated guesses to select a bearing type.

Obviously, the Friction and Roller settings are quite different and the divide is well defined. Even looking at a train's 3D model is enough to tell which is appropriate. But I get to the Low setting and I'm not sure where it belongs. Then there's the new Grease option and I don't even know what to do with that.


First of all, as I work mostly with modern content, what is the intended distinction and use case between Roller and Low bearings? I've always just used low torque bearings for passenger equipment and more modern locomotives since it makes sense for those to have lower friction, but I never got a clear picture of what exactly a low torque bearing is supposed to be, which means I might be using it too much or too little. Is it intended as just a more modern roller bearing? Is it supposed to be different technology entirely? What are some real-life train models (in America, that is) which would be considered to have "low torque" bearings? After all, with a name as ambiguous as "low torque" it's hard to know what this bearing actually is! (I'm sure every bearing manufacturer would love to advertise their bearings as low torque, even if they were plain friction bearings.)


Then there's the Friction bearing type and the new inclusion of the Grease bearing type for plain bearings. Unfortunately with the Grease type, there's no option for that in Fcalc so the chances I'd be able to come up with something reasonable for that thing's davis coefficients is low. Now, in this case, the difference in technology is clear enough; is oil the lubricant, or is it grease? All I wanted to know is where (or when) each is appropriate. Are there certain time periods associated with the Friction type and others where Grease was more common? Any differences in car types that received each of these bearings? Or is this one just a matter of personal preference? I think I have a grand total of one single boxcar in my entire install that doesn't have roller bearings, but I wouldn't know if it's more appropriate for it to use the original Friction type or the new Grease type without some more info.


Hopefully, with a nice round of clean-up, I can improve my work...and maybe eventually decide to stop making changes to it every five minutes.

[Weter]

Grease have to be pushes-out of running tracks of bearings, be heated to turn more liquid and plastic. Oil resistance must be almost constant and much smaller, as it's pure liquid friction. Only frosty weather can turn oil to grease.