How to have players stay inside a model when it is tweening?

So maybe try lowering the player’s weight a little bit not too low. This is to see how it would react.

I’ll try making their humanoid root part massless for the duration of the ride

Ok. This could help a little to stop the player from glitching!

Nope doesn’t seem to do anything.

Oh… Maybe making a script to where the player’s whole body stays attached to the model (Such as the HumanoidRoot) staying with the model and keeping it R5. Add the same speed as the model is moving to the seat. Try this and I may edit this if I get more ideas!

Ok, the highest it can work is at 200 speed, which I think is what i’ll have to settle for as it seems there aren’t any other options as of now. If anyone knows of a different method please do let me know though, as i’d love if I could have this go faster.

Ok! Well I have tried my best with this problem i’ll let you know if I have thought of any other known ways to fix this.

Have you even had a look at the previous link I posted? It deals with Anchored Parts as well.

<Jailbreak train platform system?

Your issues are because you are moving an Anchored item with CFrame and the Player doesn’t move that way.
You could try Parenting the Model to the Player as well, but if you have more than one Player in there it could get messy. I don’t know if you Parent the Player to the Model.