A rapid transit system in which a vehicle, typically comprising a train of detachably coupled cars, is suspended in an underground vacuum tunnel by permanent magnetic rails of high coercivity and propelled by gravity. For closely spaced stations, such as in urban areas, the connecting tunnel paths are smooth continuous curves, lying essentially in the vertical planes connecting adjacent stations. For widely separated stations, such as in inter-city transit systems, the tunnel paths have horizontal reaches at their maximum depth, joined at the ends by smooth paths which arc up towards each station. The magnetic suspension and the vacuum environment enables the vehicle to move frictionlessly at high speeds without contacting the rails or any other part of the tunnel. Gravity propulsion from one station to the next is accomplished by allowing the vehicle to move frictionlessly down the decending arc of the tunnel, during which time it is accelerated by gravity, and decelerating by gravitational braking while moving along the tunnel's ascending arc. Thus, the trip is accomplished by transforming the vehicle's gravitational potential energy into kinetic energy and back into gravitational potential energy. Excess kinetic energy arising from moving between stations having different elevations is supplied or absorbed by onboard linear motor/generators that provide supplementary propulsion or regenerative braking. These linear motor/generators draw and return energy to on-board flywheel energy storage units. While moving along very long straight tunnel paths the vehicle's gravitational coasting speed is boosted by flywheel energy which is recovered by regenerative braking. Since the motion is essentially without friction and since the linear motor/generator-flywheel motor/alternator system can be designed with very high efficiencies, the principle of conservation of energy applies and very little input energy is required. In the ideal case, no input energy would be required since the vehicle's total energy remains constant even while moving between two stations at high speed. When the vehicle is at rest at stations having different elevations, the differences in its gravitational potential energy are balanced essentially by equal differences in its stored flywheel inertial energy. Except for a small amount of electrical energy expended for life support systems and to make up for losses due to energy conversion inefficiences, no energy is used or required for the actual trips between stations.