Anybody else experience this? For some time now I've been seeing a problem whereby sometimes when I release the Train Brake on a loco hauling freight the loco will suddenly lurch forward, increasing speed as it does so. For example, I might be driving a loco hauling wagons and I need to decrease speed by 5mph. I slow the train down then release the brakes. As the brakes fully release the train suddenly lurches forward violently and the speed instantly increase by 10mph or more, ending up with my train going faster than it was before I applied the brake! Approaching a red light I might slow down to 2mph and then release the brake expecting to continue at a crawl but instead the train will lurch forward to over 10mph and I SPAD. This does not happen every tome I drive a loco but it can (seemingly) randomly occur in any loco, any class, made by any developer (DTG, JT, AP etc) and it can happen on any route or scenario and it can happen when hauling any freight type. It only happens when hauling freight, never a passenger train and never when driving a D/EMU. It does not necessarilly happen with the same loco every time. For instance, I could drive an AP Class 66 in part 1 of a scenario and the problem doesn't occur but then I drive the same loco in part 2 of the journey (same loco, same consist) and the problem occurs. It may only start to happen in mid-scenario but once it starts it never goes away - even if I save and resume. This is a relatively new issue (having owned TS since 2009) but it seems to be happening to me more often recently.
I have had TSC since 2010, and think this issue is caused by the couplers. There are couplers called buckeye couplers that eliminate this effect. I think that you can get them from the Railworks Americas site. You would be better off posting your question there, as there are lots of people there who modify things, and there is most likely a file in their file library to correct this.
Even though in game it is more of a bug than not in real life this actually occurs, if we are getting a kick in the pants after releasing the brake we will usually keep it in power while braking to prevent this, usually in notch 2 or 3 but could be higher depending on the severity.
Yeah I get that the lurch behaviour can be realistic but then again, if you are crawling at 2mph, you slow to 1mph (using least brakes as possible), then you release the brakes (even going uphill) you would not expect to lurch to 15mph within 1 second! So it is a "bug" of some sort. I'm just trying to figure out if I introduced it somehow or if other people get it as well. There's a nice trick comes with this "bug". If I start a loco that has caught the bug I can get from 0 to 60mph in about 10 seconds no matter what the load is or the gradient. Just apply brakes and instantly release brakes until desired speed is reached! I've started to make a spreadsheet of which combo of loco and wagons does it to find if there's a pattern or if its random, but that'll take me a good while because I don't do a lot of freight stuff. Sad as it may be, I prefer driving a Class 166 scenario to a Class 66. At my age I tend to fall asleep when doing long freight runs trevkiwi: Thanks for the info about couplers & USA etc. IronBladder: I'm up to date with the TSC version.
The bug you talk about has been like this for years - mainly with heavy trains. I remember with a heavy steel train slowing for a restriction only for the train to lurch forward when I released the brakes Something to do with the Physics of the wagons being wrong.
I remember when Donner Pass first came out, in a scenario which was removed, where you had a train with something like 100 wagons, and when you started it, the front of the train was moving, but the rear wasn't, when all of a sudden everything went flying into the air, doing twists and turns before you got a derailment error. It looked quite spectacular.
Right, based on what Peter wrote above I just did a test. Running an enhanced AP class 66 (RSC assets 66 Pack03) hauling a train of 30 MEA wagons from RSC\Class08TOC\RailVehicles\Freight\MEA\ the bug is present. I uncoupled the wagons one by one while running at speed and the lurch occured until I got down to 12 wagons when it was a lot less obvious and did not cause any speed increase. This wasn't a gradual change, the lurch was there with 13 wagons but not with 12 wagons. With 9 wagons the lurch was just a small "jolt" and no speed increase. I did the test with a train of full wagons then with the same train but empty wagons and I got the exact same result. So, it would seem to be train length to blame? (though not necessarily always the same length). Possibly due to the coding of the physics, possibly in connection with the couplings. So, at least I now know how to stop it from happining if it "bugs" me too much.
I don't experience this at all these days, so I think it's definitely stock specific. If you have Springfield Line, can you, for science, run its scenarios? What causes this kind of issue is that wagons may have flexible couplers and very different brake efforts. Really old stock like the SP SD45 and SD70 has wagons and especially the caboose (brake van) with extreme effort (strength), causing the wagons to stop even while other sections of the train still move at significant speed (10-15mph even). This causes that after stopping with minimal reduction (15psi), the loco will move back - my solution was to stop in waves (apply-release-apply-release) and upon stopping, apply a lot (50-80%) to ensure the loco is stationary. I had a similar effect on Canadian Mountain Passes where moving between cameras 1 and 3 caused significant loco movement. Of course it only affects the scenario where you stop on a 2.4% downgrade after the tunnels. So physics simulation is likely simplified. Not 12 wagons, though. As such, unfitted stock may cause this a bit more, given that it bunches up on fitted sections. But it shouldn't be too excessive. When you release the brakes, the energy in the compressed couples will cause them to push the loco forward. It's the inverse of how most US stock behaves upon starting a train - you apply power, the loco instantly goes to 1-2 mph, and then it keeps pulling, maybe decelerates a bit. (It is somewhat realistic but also practical for the sim's limitations, too rigid couplers cause various issues, consist splits or explosions.) Something else you can do is apply less brake force, because it should reduce the bunching up (coupler compression) and the resulting push. Those old SP locos aside, I've been taught to use minimal brakes and I may experience this even less. But I don't recall this issue in any of the last 10-15 DLC I played, at least.
The newer wagons from RSC/DTG seem to be better - I like running the Megafret wagons that come with the 92. I have set up a realistic train of 34 wagons with Less Co containers and no problems It might be worth doing some tests with DTG or AP or a European maker. VR or 3Dzug I think the newer stock won't have this problem
Here is another thread that may help. Tutorial - Looking For A Tutorial To Do Coupler Mods | Dovetail Games Forums
