Bridging equipment may be available, but frequently not where you want it when you want it there. This system could be carried in one vehicle and erected in a much shorter timeframe than a bailey or girder bridge,
As for steering, like in a train the cables and the groove in the wheel adaptors would make it very difficult to steer out of. The biggest problems would be the security of the four ground anchors, making sure its level and use in high wind areas may induce swinging. Remember they use cable ways for ski lifts and the cable almost never comes out of the wheels and a similar system is often used in crane systems, particularly when working over valleys and dam building (although the CoG is usually below the cable.)
Wasn't this a design project from Chertsey or somewhere?
