Wheel Slip on steam locomotives
#1
Posted 09 March 2022 - 03:37 PM
Some locomotive types were more prone to this phenomenon than others. Also, the effect is much more likely to occur with a heavier train or where the rail surface is compromised, for example, during wet or icy weather, or when there is oil or leaves on the track.
Open Rails only has wheel slip set up for diesels and not steam locomotives as far as I am aware. I still have the original MSTS installed on my PC and looking at steam locomotives in there it does a much better job with wheel slip when it comes to steam locomotives vs Open Rails. Why doesn't the Open Rails team just put the coding for steam locomotive slip from MSTS into Open Rails and then tweak it later on? It would be a lot more realistic then what we have currently in Open Rails. Open Rails reacts like this locomotive in this video. Maybe we should add sparks to the wheel slips as well when it gets that violent. Another thing to think about when it comes to wheel slips is it is possible to suck the fire right out of the firebox when its that violent because of the draft it is creating.
Brandon
https://www.youtube....xNMh0PFwfo&t=5s
#2
Posted 10 March 2022 - 10:58 AM
#3
Posted 10 March 2022 - 11:21 AM
ATSF3751, on 09 March 2022 - 03:37 PM, said:
Did you mean that the Open Rails team should extract the Microsoft's code from MSTS and copy it into Open Rails?
The Open Rails team has never had access to the code inside MSTS, so we have to create our own. That's part of the fun for coders.
#4
Posted 11 March 2022 - 09:53 AM
ORTS uses different physics, so many MSTS-tuned steamers turn "crazy", as they weren't configured properly, though MSTS allowed that.
So the work of reconfiguring, using adequate parameters is needed in such cases.
#5
Posted 11 March 2022 - 12:32 PM
Brandon
https://www.youtube....h?v=upw1PAiTG7Y
https://www.youtube....h?v=OqUYjRzUis4
https://www.youtube....h?v=T9UYYyDOJXQ
https://www.youtube....h?v=kj6M-xMw0yY
https://www.youtube....h?v=pl59l2ilfRM
https://www.youtube....CqFfso1Q&t=256s
#6
Posted 11 March 2022 - 05:25 PM
ATSF3751, on 09 March 2022 - 03:37 PM, said:
Wheel slip for diesel/electric locomotives occurs differently to steam locomotives, and therefore cannot be compared directly. It is thus implemented differently in OR for each of these types of locomotives.
For example the rotation force applied to a diesel/electric wheel is constant throughout the full wheel rotation, whereas on steam locomotive it varies due to the gearing of the wheels. Also a lot of diesels/electrics have some form of slip control that reduces the force on the wheel when slip starts to occur. A steam locomotive requires the driver to manually control the wheel slip.
ATSF3751, on 11 March 2022 - 12:32 PM, said:
Typically when wheel slip occurs, the friction between the rail and the locomotive wheel decreases significantly, and hence if left uncontrolled the wheels will accelerate to a very high speed. The only way to bring a wheel slip under control is to reduce the power to the wheels, ie close the throttle, or in some instances use the reverser (though many drivers do not agree with reverser control of wheel slip). In the second video it is very clear that the driver is closing and opening the throttle to try and control the wheel slip as it pushes the other locomotive into the shed.
ATSF3751, on 11 March 2022 - 12:32 PM, said:
This page describes an uncontrolled wheel slip scenario, and subsequent damage.
It will be noted from the description that the wheels reached a rotational speed of 140mph before the force to the wheels was removed by the destruction of the cylinders and the wheel motion gear. Presumably if these elements had not failed when they did, then the wheel rotational speed could have increased to an even higher speed.
So just like in real life, wheel slip needs to be controlled otherwise excessive wheel rotational speeds can occur.
#7
Posted 11 March 2022 - 11:08 PM
steamer_ctn, on 11 March 2022 - 05:25 PM, said:
That is exactly what can happen, and whilst OR models the significant increase in speed, it is forgiving of the driver, by currently not destroying his valve motion at excessive wheel speed. This could be included in OR to motivate the driver to control any wheel slip.
Please don't include that unless you can give us a faster way to close the throttle. Even though you have to use physical force in real life, most drivers can do this very quickly. In OR if you are outside the cab, it seems like you have to keep your finger on the A key for a long time to achieve the same.
#8
Posted 11 March 2022 - 11:13 PM
Wheels slip briefly as you pass over a small patch of low adhesion - due to loco standing and oil and water dropping perhaps - and that grip is regained even before the driver has closed the regulator as the wheels move on to drier or cleaner rail or somewhere that has already been sanded.
#9
Posted 12 March 2022 - 03:58 AM
Hello.
My mate tought me one hack:
When You correct "https" to 'http" in YouTube links, there will be small windows with video in your post, instead of just links.
Sadly, this works not always: then link text turns gray and stops redirecting to YT: roll your edition back to https then.
#10
Posted 12 March 2022 - 05:52 AM
darwins, on 11 March 2022 - 11:08 PM, said:
Then what about introducing (another!?!) keystroke that sets the throttle to zero (or some appropriate low percent) in say half a second to try to more realistically respond to wheelslip? Perhaps the throttle reduction time and reduction level could be specified in the eng file as I'm sure they would vary somewhat between different engines.