Wheel slip

[Strange Bread]

It makes trains almost useless. It must be strongly reduced or fully removed from the game.

[pontfogel]

It's basically the only difficulty encountered when building trains so I think it should remain, but it needs to be implemented differently. Less weight on the wheels should mean they're more prone to slipping, not the other way around.

[SParoxysm]

Wheel slip in general (trains and cars) needs to be looked at. I find myself having to put 10+ sets of wheels on my trucks just so they don't slide like they're on ice (that's with the tires set to High Grip).
For the trains, it seems like you hit a certain speed and wheels just slip no matter what, and weights a factor. With my engine alone, it happens at ~75m/s. With added cars the speed gets lower and lower. With 3 cars attached, it hits 25 m/s and just slips no matter what. I can't do anything to get past this ceiling, doesn't matter how I adjust gearing/throttle.
I feel like the force of gravity needs upping? Things are a little too "floaty" in general in this game.

[Strange Bread]

Yeah, that's a crappy tuned thing

[GrumpyOldMan]

The issue is that adding mass doesn't increase traction.

Build a light car with electric motors and nothing else, see how it can easily climb the steepest inclines.
Then add mass blocks, doubling the weight you'll start to notice how the added mass adds inertia but doesn't add traction, causing the vehicle to slide around.

Nothing much you can do other than using the biggest high grip tires or tank tracks/xml editing.

[Strange Bread]

Mass should not add traction, but it should add grip. It works so IRL.

[Neon Samurai]

The modeling for wheel slip at least for trains is completely wrong. Weight should add to traction, not take away from it. Locomotives are also most likely to slip in the real world at low speeds, and it comes from applying too much power at once when the train is stationary (or too heavy a load that the train cannot apply enough power to overcome the stationary weight of the consist without exceeding the traction), or when the tracks are more slippery (rain and snow). At higher speeds the locomotive cannot deliver enough rpm and torque to break the traction to the rail on level ground, because of the momentum the locomotive has.

The way the game handles it all is very weird too. For example I have a loco that I cannot fix, at any speeds over 50kph, the wheels under the cab skitter where they rapidly gain and lose traction, the wheels under the long hood are fine. The loco is perfectly balanced weight wise in the middle, the power applied to the wheels is identical, forwards or back, it does the same thing. I've tried everything I can think of to get it to stop.

[Switchblade 🔰]

I sort of fixed this issue with my trucks and forklifts by just editing the xml file and looking for tireGripFactor for each wheel. NotePad+ helps find and replace all entries because the game makes the code for all wheels in the file. I changed mine to something like gripFactor 5 and worked perfectly. Not too much grip so they'll still slip while under heavy torque but enough that they'll grip to the ground "realistically"

[Switchblade 🔰]

However something to note, the wheel grip factor will be removed if you edit the wheels in anyway after doing the edit in xml file.

[Philonious Rex]

I agree that wheel grip seems to need to be adjusted. I don't think it should be removed, but it should definitely be tuned better.

[Neon Samurai]

I cannot find tireGripFactor anywhere in the xmls for the wheel parts

[Neon Samurai]

Another thing I found too in my game is that the train wheels seem to have a strange issue that cannot be fixed, either the forward or back wheels spin (really they jitter were they gain and lose traction at a very fast rate) at a certain speed, and nothing can fix it. changing the weight center doesn't matter (even extreme changes in weight center do nothing), both motors have the same pipe length to the wheels, and draw from the same power source, both run at the same RPS. Flip the train around and the same wheels still spin. Delete and replace the spinning wheels and suddenly its the other set that are spinning.

Best part is when I link them, they both jitter spin.

[Ra-Ra-Rasputin]

Trains can reach 115m/s without much difficulty solely using the wheels. That's well within the speeds of a bullet train, and there are very few trains in the world that get anywhere close to that speed.

All you have to do is soften the amount of torque going onto the wheels. The usual method for doing this is a very low-tuned PID. Just remember, no matter the weight involved, smooth metal against smooth metal isn't very good for grip.

The game does have grip problems in that wheels have far too little grip in most situations. The train wheels, however have way, way too much grip compared to how much they really should have. Real trains can easily get massive wheelspin by revving too hard at 150km/h.

[Neon Samurai]

See that isn't quite true about the metal on metal. Real world trains can move absurd amounts of cargo. It's not unusual for a 3 locomotive consist to have well over a hundred cars full of cargo, and they have no problems finding the traction to get a consist of that size moving, even if the consist is not slacked out, even on a grade. You may need to add a loco or two for some of the toughest grades, but other than that they have no problems. You can get plenty of grip steel on steel, especially if you sand.

As for my freight loco, it starts doing the rapid skittering around 150 KPH with no cars, if I move the throttle past 50%.

Tractive effort that a loco can put out decreases as the train gets faster, until it reaches the point that no further effort is possible from the locomotive, and the train can go no faster. This is why wheel slip becomes less and less likely at higher speeds, because there isn't enough force going into the rails to cause the wheels to slip. This is known as the tractive effort curve and is specific to each locomotive type.

Wheel slip is most likely when just starting out, when the tractive effort available is at its maximum, and you have increased resistance in the form of static friction from trying to get the cars moving. This is why you need to start out slow with only a little bit of power to the motors. See wikipedia[en.wikipedia.org]

[Ra-Ra-Rasputin]

The only reason trains can do that is specifically because of the lack of friction, and thus, the lack of grip and traction.
Any train can have wheel slip at basically any speed. Even an old steam locomotive can be chugging flat 60km/h and a bit too much coal will make it happily wheelspin.