by Cactus Jack
Technically all bearings are friction bearings .... Roller and plain. Plain bearings are often referred to as friction bearings informally but it is technically not correct. As in #5 they are not grease filled but oil filled. There are grease roller bearings that require field lube and there are sealed roller bearings which is what most equipment now rides on.
While a "friction" bearing can lose oil and dry up and run hot, it is more forgiving than a roller bearing in failure in that the plain bearing will smoke or even ignite the lube oil in the box giving a pretty visual sense that it is hot. It normally takes a bit of time and you can run some distance if needed or initiate some field repairs. STP always worked good in a pinch. With proper tools and repalcement wicks and oil or a new bearing you are good to go. It is not like suddenly the bearing is going to end up dry, heat up and burn off the end of an axle in 600 yards.
A roller bearing though can fail quickly with almost no warning or visual or audible indication and that failure tends to be much more catastrophic hence closely spaced hot bearing detectors and set out tracks. The incidence of a failire or need to service and inspect is much lower than a plain bearing with less rolling resistance and hence is a technological improvement, but with the cost of detectors. The issue with failure of a plain bearing is that hardly any railroad, and probably no Class 1's have the tools or materials to repair one when something happens hence the general ban in standard AAR interchange. They are not banned by FRA and are legal if they meet certain inspection criteria (lateral play for instance).
The SNC does not make interchange with CPR at Saratoga, it is a trackage rights arrangement so AAR interchange rules would not have a direct play. It is most likely under contractual agreement of the trackage rights agreements. I am aware of situations under trackage rights where such things as moving plain bearing equipment have occured in the past as the agreements did not stipulate such restrictions and the equipment of the railroad using the trackage rights was subject to FRA compliance and the discretion of the tenents mechanical department.
While a "friction" bearing can lose oil and dry up and run hot, it is more forgiving than a roller bearing in failure in that the plain bearing will smoke or even ignite the lube oil in the box giving a pretty visual sense that it is hot. It normally takes a bit of time and you can run some distance if needed or initiate some field repairs. STP always worked good in a pinch. With proper tools and repalcement wicks and oil or a new bearing you are good to go. It is not like suddenly the bearing is going to end up dry, heat up and burn off the end of an axle in 600 yards.
A roller bearing though can fail quickly with almost no warning or visual or audible indication and that failure tends to be much more catastrophic hence closely spaced hot bearing detectors and set out tracks. The incidence of a failire or need to service and inspect is much lower than a plain bearing with less rolling resistance and hence is a technological improvement, but with the cost of detectors. The issue with failure of a plain bearing is that hardly any railroad, and probably no Class 1's have the tools or materials to repair one when something happens hence the general ban in standard AAR interchange. They are not banned by FRA and are legal if they meet certain inspection criteria (lateral play for instance).
The SNC does not make interchange with CPR at Saratoga, it is a trackage rights arrangement so AAR interchange rules would not have a direct play. It is most likely under contractual agreement of the trackage rights agreements. I am aware of situations under trackage rights where such things as moving plain bearing equipment have occured in the past as the agreements did not stipulate such restrictions and the equipment of the railroad using the trackage rights was subject to FRA compliance and the discretion of the tenents mechanical department.
