Hump yard operation

[csantucci]

ORTS has a big plus versus MSTS in hump yard operation, because any switch can be operated, therefore allowing wagons to run down many paths. However to simulate hump yard operation it is also needed that there is the possibility that uncoupled wagons have released brakes, so that they can roll downhill. Is this somehow already possible under ORTS?

Carlo

[GaryG]

Hello Carlo

If you have RouteRiter, look at the "Route Riter\BrakeFiles_Pro\Pro_Throttle_Brake Percentages" setups. These brake settings allow cars to both roll freely and yet will brake normally in a train.

With these settings, I had a train running on level track, uncoupled a block of cars, pulled ahead of them then carefully let them catch up to me and they recoupled.

This might solve your request.

GaryG

[conrail1]

May be in the future OpenRails will allow you to bleed off the air on cars in a yard destined for classification just like we do it in the real world.

[csantucci]

Thanks Gary, I don't have the "donateware" version of RR, but I found in the Trainsim library the original files about the "Pro" settings; I tried to modify a freight car, and in effect if uncoupled in a slope it runs down a bit under OR (as I assume it does under MSTS)! It's not a free long run, but maybe it can be sufficient. When I have time I will make tests with a hump yard under OR.

Carlo

[OTTODAD]

If you have RouteRiter, look at the "Route Riter\BrakeFiles_Pro\Pro_Throttle_Brake Percentages" setups. These brake settings allow cars to both roll freely and yet will brake normally in a train.

Now that sounds interesting but can see a problem when uncoupling such freely rolling cars in freight yards on sloping terrain, I would never build one on for that reason.

Does that mean that wagons on the downslope of a hump can be uncoupled from the rest of the train and then will roll into the classification yard, it's switches having been set for them with the new ORTS Hold down Alt and click on them function ?

ORTS now has a handbrake-off function when hand brakes are shown in the F5 HUD = : but do not know what it can be used for.

Remains the question of how to stop them from crashing into stationary wagons when they reach their destination. Ctrl-Click on the rolling wagons to apply handbrake ?

O t t o

[sniper297]

Brakemen are expendable!

Or they used to be before OSHA came along. Originally that was the way it was done, man riding on the coasting car hanging onto the brake wheel and hopefully screwing it down at just the right time. Too soon and the car comes to a stop blocking the track, too late and it gets real noisy and exciting. Later they invented retarders, hydraulic gizmos that squeeze against the inside of the flanges to slow the car down. Originally controlled by a guy in a tower, I think the later ones use computers and lasers or doppler radar or something to decide how much squeeze to apply according to current speed and distance to go. MSTS don't have anything like that, Trainz has a real basic retarder track section;

https://www.youtube.com/watch?v=k1q58LU3-X4

What I did at Combs Landing on MSTS PO&N was set the end of the yard tracks for an uphill grade, so a car coasting to the end would slow and stop from gravity;

1.jpg

And that works sort of, but the physics in MSTS didn't allow for any kind of realistic coasting so I never went any further with that idea. Design in some kind of coasting physics and a track section similar to the Trainz speed retarder could be made, main thing is to get the momentum physics realistic.

[conrail1]

Design in some kind of coasting physics
main thing is to get the momentum physics realistic.

If the physics model is correct from the ground up (rolling resistance being a part of this) then “designing in some kind of coasting physics” wouldn’t be needed, it’ll already be there.

[csantucci]

Otto, as far as I have tested with the "Pro" parameters, the cars don't run freely. They run a bit and then (presumably when all the air is out) they stop. So no problems of never stopping cars.
Of course a solution that allows bleeding off the air in the cars (as conrail1 suggests) and that foresees retarders along the tracks on the hump yard (as suggested by sniper) would be THE solution.
Let's see what will come out of the magic box of the ORTS dev team...

Carlo

[csantucci]

Well, at the end I was able to have hump yard operation on OR. I used the German freeware Ruebelandbahn, where a yard hump is present. I modified the brake parameters of some wagons accordingly to the "Pro" settings, as suggested by GaryG and reduced further to 0.1 the MaxApplicationRate parameter, to have a long enough rolling.
You can see the operation here https://www.youtube.com/watch?v=pPnCrEONu6c .

Carlo

[OTTODAD]

That's a great video, Carlo !

Looks like the rolling loose wagons hitting the static ones a bit on the fast side is not causing a problem.

Will call for new routes and additions to existing ones to provide hump classification yards.

O t t o

[sniper297]

Curious, what's the grade, how fast do you kick them, and do the train brakes work for those cars while it's in a train?

My thinking on this is since we have the retainer control now, redo all the cars so that;

1. While coupled on the train the air brakes work;
2. Add some type of control to bleed the air before uncoupling, if it's uncoupled before bleeding (and shutting off the cock to the rest of the train) the entire train goes into emergency;
3. When uncoupled from a train with the air bled off they have no brakes at all unless the retainer is set.

My guess is that the original design used some type of simplified "holding brakes" so they wouldn't roll away if originally placed or uncoupled on a grade, in real life you would use the handbrakes for that. That would be the simplest way to set it up, I assume the loose consists having the "retainer" set means handbrakes on, just redesign so the retainer has to be set for the cars to stay put after uncoupling, otherwise gravity and Isaac Newton are in control.

[conrail1]

Looks like the rolling loose wagons hitting the static ones a bit on the fast side is not causing a problem.

In the real world at those speeds it would have caused plenty of problems.

Curious, what's the grade, how fast do you kick them

Why would they be kicked if this is a gravity/hump operation?

When uncoupled from a train with the air bled off they have no brakes at all unless the retainer is set.

What good would setting a retainer do if the cars are bled off?

My guess is that the original design used some type of simplified "holding brakes" so they wouldn't roll away if originally placed or uncoupled on a grade, in real life you would use the handbrakes for that. That would be the simplest way to set it up, I assume the loose consists having the "retainer" set means handbrakes on, just redesign so the retainer has to be set for the cars to stay put after uncoupling, otherwise gravity and Isaac Newton are in control.

How about doing it like we do in the real world.

As the car ascends the hump the slack is in and the pin puller is able to get the pin on the coupler. The pin is held up as the car crests the hump and the car uncouples and drifts down the hump and through the master and group retarders. Hand brakes are not used unless the pin puller is unable to get the pin. Most operations I’ve worked in have a devise to pinch the flanges on the wheels of the car just beyond the crest of the hump to get slack to free the pin on the coupler if it is malfunctioning.

[sniper297]

"Why would they be kicked if this is a gravity/hump operation?"

If you watch the video they are being kicked on the hump. Trainz has the best built in free rolling physics but even in Trainz they need a slight kick - if you uncouple a car on a 3% downgrade it just sits there, it has to be rolling downhill at 1mph or higher before uncoupling, THEN it will accelerate from gravity. In the real world it WOULD start rolling by itself, none of the Big Three trainsims will do that yet.

"How about doing it like we do in the real world"

If it can be programmed in, obviously that would be ideal.

[GaryG]

One suggestion for the cars with the modded braking. Use one of the friction calculator versions to set the friction settings to properly reflect the weight of the car, number of axles, etc,. I use FCalc 2.0 GUI, written by Joseph T. Realmuto way back in 2004 for my number calculations.

I've released cars with adjusted Friction settings and the braking as from the Pro/Percentage directory and I do feel they roll an appropriate distance for the speed and grade without getting the feeling that the brakes were applying.

GaryG

[conrail1]

If you watch the video they are being kicked on the hump.

No I missed that, kind of defeats the purpose of having the hump but also brings up the ability of simulating flat switching.

it has to be rolling downhill at 1mph or higher before uncoupling, THEN it will accelerate from gravity.

When I release the brakes on a consist sitting on a grade it will start to roll on its own without any throttle in MSTS and OpenRails. So you are saying it is different when they are on their own without air on them?

If it can be programmed in, obviously that would be ideal.

That’s why I mentioned in response #7 that if the physics model is correct from ground up the rest should fall in place.

In order to realistically simulate flat switching or classifying cars in a gravity operation the effect that crossovers and turnouts have on the equipment will also need to be represented.