Using Railcraft 6.15.2.0 and Forge 523 on a server that is moderately to heavily loaded (average tick between 13 and 40), locomotives at max speed tend to lose their coupling with the player's cart immediately behind them. This usually occurs after a net lag spike; the entire train appears to stop, then the locomotive cruises away without you.

Occasionally carts in the rear will also somehow make their way between the locomotive and the driver's cart, causing the train to either stop or move forward and backward in an erratic manner. I think this may be related.

Is there a suggested way to handle this? I cannot rely on locomotives for primary travel as long as they are going to be running off on me.

Sorry, this is on regular tracks. And it happens on flat straight sections or curves and slopes.

Thanks for your time.

Hmm....

If it helps, I experienced the same issue in 6.14 with a Steve's cart pulling the train. I was hoping it was just an issue with that mod and cart linking.

If you need a copy of my world, I'm running Direwolf20 5.0.1 with default configs.

On High Speed Track or normal tracks?

If HS, you may need to think about reducing the top speed via the config.

I confirm, this also happens on server I play on, after a lag spike I can loose my locomotive, as it drives off into distance or my cart jumps in front of it, which breaks routing logic.

This happened to me today with Direwolfs 1.6.4 modpack. I had a Steves cart in front, me in the middle in a standard minecart and an admin anchor cart in the back. As I cruised on normal tracks, a chunk didn't render in front of me, so I logged out and in again and then my cart was behind both the others and all were uncoupled.
This was on a server, with only me online.
I don't know if it's related, but I have chunks not render on me all the time when riding this train, though it navigates just fine through the invisible chunks.

NB. i'm not requesting support, just providing feedback :)

Pushing carts is a bad idea. As is logging out/quitting while riding anything.

Just to clarify.

I wasn't pushing carts. I had a Steve's carts cart with an engine in the front. The order of the two back carts was reversed after I logged off and on again due to chunks not rendering. So the Steve's carts cart was still running, but regular cart and admin anchor carts were uncoupled and changed places.
I'll keep your point about relogging while riding in mind and I wouldn't have done it normally... it was just the issue with me not seeing my surroundings that made me try it :þ

Ok, since this isn't likely something I will ever be able to fix, closing.