As mentioned in my Beam Engine post I have always been interested in Lego Pneumatics. Over the years I have made some creations which I thought I would share with you.
One of the first things I tried to make was a motorized pneumatic switch using an old style 9v motor. It uses the spring from the Lego Technic hockey players to re-center the value.
I also had a go at making my own pneumatic single piston engine however, I went a bit further and build a Lego compressor to power it. This was great fun!
After the beam engine (post found here) I had a go at making a pneumatic train that works like a real steam train. This requires a lot more pressure than the single piston engine above however does not require a flywheel.