I spent a while in Bristol Temple Meads station on Monday a rather beautiful building. It was the hub of Brunel's Great Western Railway.
Reading the wikipedia entry on Brunel I read about the atmospheric railway . A mad idea when you look back in retrospect.
The first experiments were done in Dalkey Ireland, and it was the success of this trial that peaked Brunel's interest.
It's difficult to understand how this system would work beyond getting a train from one destination to the next. II think one of the major reasons the system failed beyond the rats eating the vacuum seal was the difficulties of making points work..
You can read more about the system at Tally-Ho the Vacuum.