For cargo trucks and possibly convecs and other vehicles.
Earthworker or other similar vehicle builds a monorail.
Monorail is not raised above ground, like a single train track.
Units can drive over this rail.
Sole purpose is to further increase unit speed in addition to paving. The player would be able to get greater truck speeds from mines, and along other programmed routes. This could allow faster transportation of all game units if desired, giving a greater mobility, while allowing the same dynamic battle and initial situations to exist. Rails would be easy to destroy, and might or might not damage like a tube when broken (electric shock). The power requirements would be high, causing more power genearation facilities, to be made. The more vehicles on a rail at once, and the speeds attained (also dependant on tech) would affect power consumption. Perhaps a 100 energy per vehicle on the rail cost? The rail would have an initial tech, to allow domestic vehicles. Additional researches for enhanced rails, and vehicle compatibility, (light med and heavy chassis design) could be made. The power requirements would become a large determining factor if a player were to build a rail to ferry units from a factory, to the front, or to transfer groups of units. 20+ units at a time would cost much energy to transport, and speed would decrease along rail if not enough energy were present. Units on rail, may or may not be able to perform their functions while in transport. Exiting rail, could be done at any point by "detaching, thus eliminating the need for a terminal like device.
Just throwing it out there, i did scan the threads in here and did not find anything exactly like this. Although i think a monorail had been touched upon somewhere.
-Peter-