Rabbit animation by servo

Rabbits animated to pop back into their burrows at the approach of a train.
This project has gone through several modifications as the original servo was not powerful enough.

A train, from either direction, is detected by two light dependent resistors in the track ballast, connected to an Arduino Uno microcontroller that drives the animated rabbits and some other things..
The servo is being replaced with a small motor/gearbox that drives a snail cam that pulls the rabbits in (against springs in their burrows. This will drive the rabbits using a length of piano wire down a surplus bowden tube for a 3D printer.
The snail cam should allow the rabbits to come out slowly, but upon being alarmed the follower will drop down the cam, snapping the rabbits in fast.
The project also includes a servo driven mini me standing in front of my caravan and waving when a train goes past. and a red kite that does an occasional glide around the mountain top - driven by a small stepper motor. (th