Bill,
We use a pneumatic piston on our club layout but it's a curved, double line lift bridge and frequently raises havoc due to changes in humidity (swelling and shrinking the length of the bridge). It's a very good solution that I think we spent about $50 for the piston. But looking at your pictures, it looks like your bridge swings very close to your suspended ceiling. If so, the cheap part me says, "How about a 2x4 hanging down from the overhead to catch the bridge?"
