The invention relates to a rail transit rail transfer mechanism, a locomotive and a personal rapid transportation system, wherein the rail transit rail transfer mechanism comprises a first guide part;the first guide part comprises a rail transfer wheel and a synchronizing mechanism, the synchronizing mechanism is fixed to the locomotive, the rail transfer wheel is connected with the synchronizingmechanism, the synchronizing mechanism is used for driving the rail transfer wheel to make contact with the rail, and the rail transfer wheel is used for guiding the locomotive to transfer to the rail leftwards or rightwards along the rail; the invention provides the rail transit rail transfer mechanism which is compact in structure, reasonable in design, and good in rail transfer synchronism; the rail transfer time can be reduced, the system operation efficiency can be greatly improved, and the rail transfer process is stable; the rail transit rail transfer mechanism can effectively relieveor eliminate the serious beveling phenomenon caused by attaching the rail from bottom to top in the prior art, can facilitate safe and stable operation of the locomotive, can reduce the abrasion lossof the rail transfer wheel, and can prolong the service life of the rail transfer wheel.