[NickonWheels]

Hi, folks. I´m NickonWheels, just joined ElvasTower mainly because some shortcomings kept me up all night. One problem I have is not specific to any route or locomotive/wagon, but rather it´s a general issue: friction at zero speed.

The current way ORTS calculates this (I assume by my observations) is just taking the mass of the vehicle and what you wrote into ORTSBearingType, then mixing it with a non-linear equation. My example of showing this is this MILW EP-3 quill I recently modified with the lines ORTSDavis_A, ORTSDavis_B, ORTSDavis_C and ORTSBearingType on all three parts.
[attachment=101199:1.JPG]
As you may can see the differece between 55,5 short tons and 188 short tons is smaller than what ORTS does calculate about their friction, but I think this is too much friction in general.

I curiously looked up on Wikipedia, found the Timken 1111, a 4-8-4 steamer built in 1930 and featured roller bearings on all axles. It reportedly only needed three men to be set into motion. After some research on Google I found out that three men averagely have a pushing force of about 3000 newtons or 674 pounds. After I reworked the EP-3 with roller bearing, it looks like
[attachment=101200:2.JPG]
I like to remind you that this EP-3 weighs 299 short tons compared to the Timken 1111 which weighted a total of about 360 short tons. Now you can see that having such an engine with a standstill friction of less than 674 pounds total is not possible with the current way ORTS calculates this. It doesn´t even care on what the value of the vehicle´s inertia force ORTSDavis_A is. This problem may be well known to someone who likes the UP BigBoy pulling a realistic freight train (where all vehicles have these ORTS friction files in them), which might not be possible to start (or with realistic coupling strain maximum values the couplers will just break).

I think the impact of the bearing type has to be reworked. The most obvious idea would be to scrap ORTSBearingType completely and replace it with something like ORTSZeroSpeedFriction where the user can insert a numerically value (like when having ORTSDavis_A value of 1000 and roller bearings ORTSZeroSpeedFriction might be 1050 or so), but this basically means the users had to modify their .end and .wag files, which is not acceptable (I personally have about 1000 files or so).

A better case would be to keep ORTSBearingType, but use it in conjuction with ORTSDavis_A, which mostly is based on the vehicle´s mass. My personal idea was to expand the "Experimental" screen (when you start OpenRails, click on options than going to "Experimental") with three lines, one for each of the used bearing types friction/roller/low, where the user could insert a multiplying value that is based on the ORTSDavis_A value and what kind of bearings the vehicle have. I made a small sketch just to show how it could look like
[attachment=101201:3.JPG]
For example if you have a locomotive/wagon with ORTSDavis_A ( 1000 ) and the ORTSBearingType is "Roller" and you have inserted 1.05 in the roller column, friction at zero speed should be 1050 newtons (a bit of rather simple math).

I think this would be the more preferable way as not using these ORTS lines at all is unrealistic too, users would not have to rework as many files and it might not be so difficult for the ORTS Development Team to pull of. It would be a piece of code which asks every .eng and .wag about what kind of bearing they have, check the value of what the user wrote into the respective lines visualised by the sketch above and what the value of ORTSDavis_A is.

What do you think about this? Worth considering? What you think are good multiplier values for the bearing types. Thanks for replying...

[steamer_ctn]

NickonWheels, on 08 December 2019 - 12:35 AM, said:

I curiously looked up on Wikipedia, found the Timken 1111, a 4-8-4 steamer built in 1930 and featured roller bearings on all axles. It reportedly only needed three men to be set into motion. After some research on Google I found out that three men averagely have a pushing force of about 3000 newtons or 674 pounds. After I reworked the EP-3 with roller bearing, it looks like

This was a publicity stunt, and may not be an accurate reflection of the physics involved. There are a number of unknown factors that could influence how the locomotives was started.

For example the Timken 1111 was also successfully pulled by three and four ladies (see timken publicity photos). Given the ladies footwear, it is a bit hard to believe that they were able to get the locomotive moving from a standing start, more likely that they were able to maintain the motion of the locomotive once the initial inertia was overcome.

This article published by Timken, and provides a fuller description of the locomotive and describes the benefits of roller bearings. The main benefits are in reducing the running costs of the locomotive. Suffice to say that it took some time before railway companies universally adopted roller bearings.

NickonWheels, on 08 December 2019 - 12:35 AM, said:

This problem may be well known to someone who likes the UP BigBoy pulling a realistic freight train (where all vehicles have these ORTS friction files in them), which might not be possible to start (or with realistic coupling strain maximum values the couplers will just break).

So what is a realistic starting load for the Timken 1111?