Note the massive bridge carrying this train. It is designed so that it can carry two trains fully loaded passing each other in opposite directions. This might happen only occasionally, but the bridge needs to be able to carry that much weight all the time. Consequently, the investment that went into building the bridge might only be used for a few moments once or twice a week. This would give it a productive efficiency of less than 1%. Even steam engines were better than that!
RailPlane avoids this problem by distributing the weight of the train throughout the whole network of rails. Distributing the load results in lower concentration of loading which allows for lighter, less expensive structure to support the load.
Both high-speed trains and light rail trains stop at stations. RailPlane on the other hand, operates in the same fashion as highways; vehicles get on, vehicles get off, but traffic keeps moving. Not stopping at stations, results in a higher average speed and greater capacity. The combination of these factors results in a system that is competitive with high-speed rail, yet far less expensive.