A modular rapid transportation system is described which features transport modules for carrying passengers and/or freight, high-speed, constant-velocity conveyors for transporting the transport modules from station to station and variable-speed transfer vehicles at the stations capable of matching velocities with the high-speed conveyors for loading and unloading the transport modules onto and off of the conveyors. A station in the system is located between at least two oppositely-moving, constant-velocity conveyors and includes at least two closed-circuit, overhead rails above the constant-velocity conveyors.The transfer vehicle travelling on a rail accelerates from a loading/unloading section of the rail with a transport module and matches the velocity of one of the constant-velocity conveyors, transfers the transport module to that conveyor and then moves to a storage section of the rail. The empty transfer vehicle then accelerates from the storage section of the rail, matches velocities with the oppositely-moving, constant-velocity conveyor, attaches to and removes a transport module from that conveyor, accelerates with the transport module back to the module-loading section of the rail.A system of detectors located at each station provides signals, enabling automatic loading and spacing of modules on the conveyor. A manual override control system is provided for overriding the automatic system.Inherent fail-safe design features are provided for preventing collision of transport modules during the loading and unloading processes.