I've been working on and off on making a level crossing for some years now. I've bounced between the electronic and purely mechanical option but finally come back to the electronics using an Ardiuno to drive a pair of stepper motors with simple micro-switches to detect the limit of travel. There is a 3D printed unit under each gate which can actually drive the gate nearly 100 degrees, this allows some over-travel in each direction to take account of the back-lash on the gates caused by there being a little bit of movement in the joiners which couple of top of the stepper motor with the bottom of the gate.

I've obviously got a lot more bedding in to do and also some additional bits like the red targets on the gates and some small wicket gates. But for now it is working reliably and that is a good step forward.

I've put a short video on Youtube to show it moving.