Provided are a rail vehicle traction system and a rail vehicle. The rail vehicle traction system comprises a natural gas traction system and an electric traction system. An output end of the natural gas traction system and an output end of the electric traction system are each connected with an input end of a traction drive system. An output end of the traction drive system is connected with a traction motor, and the traction motor is used for providing power for rail vehicles. The rail vehicle can select a suitable traction mode according to the railway network environment, and under the work condition without contact networks, power is provided for the rail vehicles by using the natural gas traction system; under the work condition with the contact networks, power is provided for rail vehicles by using the electric traction system, and the rail vehicle can thus be suitable for both electrified railways and non-electrified railways at the same time.