[Woodfyr]

I had this alarm yesterday while running the "East End Switching ((Part 1), Seligman OR. Message to the affect "Failed Bearing on Carxxxxx)(do not remember exact wording).
I did get a 'yellow' car showing on the F5 - Consist Information.
Running OR MG23.

[steamer_ctn]

Thanks for the feedback on the operating rules for hot bearings.

[darwins]

I could see the need for a third bearing type here as well as ORTSBearingType ( Friction ) and ORTSBearingType ( Roller ) there should perhaps be ORTSBearingType ( Friction_grease )

The logic for this is that the old type grease friction bearings were much more prone to running hot.
I thought if this could be done by using a MaximumSpeed ( x ) statement in wagon files but I suspect not.

The most likely things to get hot boxes were:
(a) loaded goods wagons with older grease type axle boxes running for prolonged periods at above 25 or 30 mph.
(B) loaded goods wagons with oil axle boxes, running for prolonged periods at higher speeds
© older steam locomotives with inadequate bearings
(d) other steam locomotives with friction bearings - ones with better bearings much less likely than © so could a probability function be put in eng or wag files with default set fairly infrequent.

The reason I think not to use maximum speed would be that wagons with grease axleboxes were not much good above 30 mph as suggested in the operating notes.
On the other hand friction bearings lubricated with oil were considered acceptable in later years for passenger carriages and locomotives running up to 90 mph.
Wagons with friction bearings lubricated with oil were mostly limited to a maximum of around 50 or 60 mph not because of the bearings but because of short wheelbase making them more prone to derailment above about 60 or 70 mph.

Apart from being more prone to running hot the grease type of axle box would have had a higher starting resistance than one lubricated with oil, especially in cold weather.


Not sure I like what this board has done with my b and c but will leave it as it looks fun.

I should add that in UK grease axleboxes were used on most goods wagons built before about 1890 or 1900 and continued to be used on many unbraked short wheelbase private owner wagons manufactured until about 1940, particularly those used to transport coal.

[ErickC]

Do plain and roller bearings us the same algorithm for calculating the heat-based friction parameters? I feel like the added friction on modern roller bearings is really excessive. I'm having a real bear of a time getting a cut of cars moving on level ground that ought to not present much of a problem (1848 tons of lading with a single GP38-2 - child's play in real life), and all of the other parameters - car weight, tractive effort, friction - check out. The locomotive is delivering the correct traction force, the cars weigh as much as they ought to, the bearing types (roller) are correct, and I redid the friction parameters in FCalc2 twice. When I warm up the bearings by running at speed for a while, then the cars move with the appropriate amount of power. If I run an older version of OR from before the feature was implemented, I also have no problems getting the cars moving. I'm mulling over compensating by modifying the friction parameters.

[copperpen]

ErickC, on 09 August 2019 - 05:59 PM, said:

Do plain and roller bearings us the same algorithm for calculating the heat-based friction parameters? I feel like the added friction on modern roller bearings is really excessive. I'm having a real bear of a time getting a cut of cars moving on level ground that ought to not present much of a problem (1848 tons of lading with a single GP38-2 - child's play in real life), and all of the other parameters - car weight, tractive effort, friction - check out. The locomotive is delivering the correct traction force, the cars weigh as much as they ought to, the bearing types (roller) are correct, and I redid the friction parameters in FCalc2 twice. When I warm up the bearings by running at speed for a while, then the cars move with the appropriate amount of power. If I run an older version of OR from before the feature was implemented, I also have no problems getting the cars moving. I'm mulling over compensating by modifying the friction parameters.

Have you tried ORTSBearingtype (Low )?. This mimics the newer low friction roller bearings.

[ErickC]

I did not realize there were two different roller bearing types available to us - I must have not read the manual as carefully as I thought. I switched them out, and everything's fine now. Thanks!

[R H Steele]

There might be something else overlooked. I tested a GP38-2 using an OR Std_Eng file - using the load specs Erick posted.

One test with loco fitted with roller bearings, 2nd test with low torque bearings, also changed bearings in the test load wagons -- used roller, low, and friction for them.

In all tests the single GP38-2 started and pulled the loaded consist on a flat grade from a dead stop.

Took more power with Loco-Roller and Wag-Friction, of course. Loco-Low --- Wag-Low was the easiest -- as expected.

[systema]

ErickC, on 09 August 2019 - 05:59 PM, said:

Do plain and roller bearings us the same algorithm for calculating the heat-based friction parameters? I feel like the added friction on modern roller bearings is really excessive. I'm having a real bear of a time getting a cut of cars moving on level ground that ought to not present much of a problem (1848 tons of lading with a single GP38-2 - child's play in real life), and all of the other parameters - car weight, tractive effort, friction - check out. The locomotive is delivering the correct traction force, the cars weigh as much as they ought to, the bearing types (roller) are correct, and I redid the friction parameters in FCalc2 twice. When I warm up the bearings by running at speed for a while, then the cars move with the appropriate amount of power. If I run an older version of OR from before the feature was implemented, I also have no problems getting the cars moving. I'm mulling over compensating by modifying the friction parameters.

I believe there may be other issues with start resistance. I would expect start resistance for a bearing to be directly related to the weight of the wagon, ignoring temperature factors. What happens in OR at the moment is that the start resistance varies as force per ton weight such that the higher the wagon weight the higher the proportional factor. That is the specific resistance increases with increase in weight. I think the proportion should be uniform across the weight range.

For example a Friction bearing has a start resistance of 12.23 lb/t-us for a 30t-us wagon and 20lb/t-us for a 100t-us wagon. I would expect the specific resistance to remain at say 9lb/t-us whatever the weight of the wagon. Similar anomalies apply to the roller and low bearings. This means that for very heavy trains such as those used in North America the train may not be able to starting some circumstances whereas in real life it would easily start. This becomes even more of a problem if driving in rain or snow in OR.

The start resistance can be checked easily for an individual wagon by using the forces HUD.

Mick Clarke
MideastPlus