Well I've never encountered what you described in terms of cars being left behind. But the part about getting within 2 car lengths and all hell breaking loose? A past post of mine I will quote, might shed a little light on this phenomenon that I personally call the
"physics bubble" ......
Let's keep it real here. The coupler issues are only PART of the problem when it comes to the physics. Load up Cajon Pass in free-roam where you start in Victorville. Pick the loco of your choice and ditch the cars connected to it for convenience. Run the loco all the way back to Barstow and try to pick up the line of cars on track 24 of the yard. You won't even get close enough to attach your coupler to it cuz it explosively derails the line of cars instantly when you get within about a car's length . That's one of the many issues with the physics.
Speaking of physics... I've discovered that rail assets have what I like to call a "Physics Bubble" surrounding them. I discovered this when trying to make behemoth size monster trains with a HUGE amount of cars connected together. Cuz when I'm approaching a super long line of cars to couple to, my framerate drops from like 30-40fps down to 4fps according to fraps. I used fraps to get a FPS count cuz Railwork's counter won't show below 14fps. It looks weird for your loco to go into bullet-time when you get close to a huge line of cars when it was just speeding along earlier before it.
Then once I'm connected, my framerate pops up to a whopping 7-8fps and pretty much stays at that while I'm pulling the train. Even turning TSX-OFF and every setting to off or the lowest it could go, didn't change this fact. So MIN or MAX setting, you will hit this bullet-time. At least on my rig. It's this "Physics Bubble" I'm hitting when the cars on track 24 derail before I touch them as well.
That physics bubble might be the issue you are talking about. TS2013 starts including the cars or engines you are about to couple to in it's total physics calculations of your engine you are using about a car length or so before you couple to it. At least that's been my conclusion. Physics bubble simply means the point at which the simulator starts combining the physics. You'd think it would happen only when you have coupled or are pushing against the couple of the other assets. But my observations have proven otherwise.
When I made my HUGE monster trains and then saved, a lot of times the train would derail instantly as soon as I loaded my save up the next time. So I came up with a trick of stopping my train, uncoupling and then saving to avoid that issue. But I figured out that you have to move a few car lengths away from your huge trains before saving. Otherwise it would be close enough to still be in the "physics bubble" and would STILL derail instantly. So I always detach and move away from the trains I am pulling if they are long and THEN save my game. It seems to be less of an issue with smaller train sizes and you can usually save with no problems while still connected to the train. But with monster size behemoth trains you assemble yourself.... it's a MUST that you must distance yourself before saving or you risk having to start from scratch.
Hope that helps a little!
