BBroich transformed a famous set - 4558 Metroliner to a monorail train:
A photo is a link to gallery, you can find there few nice monorail trains.
Now when we start talking about monorail, I'll tell you a few words about it. This system was used first time in 1987 in Space set - 6990 Monorail Transport System:
System is based on track with one rail in the middle of it. It's underpined by brackets. It needs a special motor. Now these parts are very rare and expensive. IMHO the best monorail set is 6399 Airport Shuttle:
And announcement: I'll propably employ two co-bloggers - Legofan and Sprinter94 (Krzysztof) from KMFL (Polish Young Lego Fans Club).