# Best way to construct an articulated train

Hello!

I’m trying to build a multi-carriage train in Blueprints that will follow a spline path disguised as tracks. I’m trying to figure out the best way to link the carriages to the bogies, and the carriages to each other and am finding it difficult.

I have tried physics constraints between the car and the bogies but it seems like they are great for hanging objects, but not so great for holding objects up (which is what the bogies will need to do to the carriage, as they are the ones locked in position to the track). The main carriage body falls down though the bogies, and has a hard time moving if I turn on collisions between the two of them.
Even though I’ve been slowly improving the physics, the movement with this option seems to be pretty glitchy overall.

I’m now trying just offsets in location based position along the spline, but there’s no physics at all which I’d like to include to incorporate cab sway and flexing of the overall train when accelerating and decelerating.

Another option I’m yet to get around to is making it all with a skeleton rigged to each part.

So my long winded question is, which is the best one of these three (or other?) options are best for making a vehicle like this?

And further to this, can I constrain the bogies to a plane that is aligned with the spline and still have it compatible with the setup?
I can’t seem to find any nodes to set the plane on the fly, so I’m having to write my own physics for the momentum of the bogies. Ideally I’d like to use the local spline direction at each position along the spline as the constrained plane.

Cheers!

If it were the wagon driving everything (and the one staying in the middle of the track) then the wheels will be off the rails as the train goes around a curve.

Id create a blank skeleton chain with the root being the train and each successive chain being a wagon , make it whatever length the train could max be, and use sockets to slap wagons on, make the skeleton wagons driven by physics with constraints representing the max rotation their connection allows so they bent and follow the root around like in the cable examples.

that would propably require some tweaking to get the right look but should work , tbh only ever used this for making a lantern that swings in the wind though X_X

I think you can avoid that by placing the spline attachment point in the middle. That way you would be able to simulate the curvatures needed for spline railroad tracks.

I thought of this as a possibility too, but I don’t know if UE4 supports creating skeletal meshes in-editor. That’s why I suggested using sockets instead as it circumvents this obstacle.

Alternatively place them near the sockets to emulate bones in a skeletal mesh. The rotation might not be super accurate this way however.

I’ll give this a try. cheers!

If it works out well can I get you to make it an answer?