How would you handle a train system?

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I’m working on a futuristic game where trains are the primary mode of transportation (there are no cars). The trains won’t be player-controlled—they’ll just move along predetermined routes for players to see and interact with (e.g., boarding, disembarking).

The aesthetic I’m aiming for involves trains floating above the tracks, so physical tracks are not an option. This has left me unsure how to handle the trains’ movement smoothly and efficiently, to not lag out lower end systems. I am also going to have multiple of these trains (around 20ish different lines), so efficiency is a priority.

The first game that came to mind with a system like this was Jailbreak, where the trains move along a path without player control. I’d love to hear how other developers would approach this or have tackled similar systems in their own games.

I’m not looking for specific code, just your thoughts on how to design this. For example:
• Would you use waypoints and tweening for movement?
• Would spline-based paths be better for smoother curves?
• How would you handle things like speed adjustments (e.g., slowing down at stations or on curves)?

Any advice or opinions would be much appreciated!

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To make a train system, if you want to rely on tracks on where it goes, you can make a train model then weld all of the parts/unions/meshes so that they move when the train models move. You can add a vehicle seat and a velocity and a script so that it moves automatically.

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You definitely want to use CFrames to move your train. The most performant way to move models isn’t Model:PivotTo(), that method is actually quite bad especially with a non-welded model.
The most efficient way is to weld to model and only keep the rootpart anchored, and then changing the CFrame of the rootpart (you can even use a tween on it or workspace:BulkMoveTo() for even more performance)

For curves, splines will be the way to go. Bezier curves work well and are simple, but calculating their length can only be approximated, by getting many points along the curve and getting the distance between those points. However, that can be precalculated

For updating the position of the train along the track, I’d suggest storing the position of the train along the track, and incrementing it by dt*speed every frame. You can change the value of speed to make it slow down (however you’ll need to have some code to get it to stop at the correct position) . Using the new position, you can find on which track segment it belongs, and where along that track segment it should go

A function of t, where you give it time and get the train position is possible and would provide an exact position of where the train stops, but that is more complicated, involving calculus for acceleration

DO NOT update the position of each wagon separately, they will eventually desync, and the spacing between each wagon will get messed up. Calculate the position of each wagon from the position of the head train (or the last wagon)

To make characters move when standing on the train, there is some simple CFrame code (simple relative to CFrames lol) for it that I can provide

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Thank you! I’ve been searching around for solutions for a day or two by now, and moving cframe seems the best. I’ve been messing around with bézier curves. Players being able to interact with the train isn’t the highest of priorities since they will most likely be client sided due to mechanics I’ll add later, and the trains act as fast travel.

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