The Rolling Roof

Above the rail car will be a conveyor.  This will be completely black, but will have a grate cut into it, which will slide past the car at the same rate as the rope.  There will be lights inside the conveyor, to shine light out from the grate, and this will give the spies the impression that they are passing ventilation shafts as they travel down the tunnel.

I have also put rope-lights on either side of the conveyor.  These will reinforce the feeling of movement by flashing the lights in series along the rope.  The pistons on either end can be used to bend the rope-lights, and give the impression of going round a turn in the tunnel.  This can be combined by tilting the car on the jacks so they really feel like they are going round the bend!