Am traveling in Colombia now and spent last weekend in Medellin. That city has a terrific above ground metro system but what really impressed me were two cable routes that are integrated with the metro. The cable system is designed to connect poor areas on adjacent hills to the center of the city.
A cable car comes along every 25 seconds and each car holds ten people. There are four stations for the cable network that I took and the trip from the bottom to the top takes 20 minutes. The system is not designed for tourists but for the regular users of mass transit. It is totally cool.
Do a Google images search for metrocable and see what I mean.
Am in Bogota now and that city is dealing with rapid mass transit by building dedicated bus lanes and using reticulated double buses on those routes.