The utilization of installed power capacity of internal combustion engines (ICE) in motive power units (especially in shunting locomotives and locomotives for industrial transport) is very low. The mean output of ICE in this operational mode is about 15 - 20 % of its installed power. The result is that most of the time the internal combustion engine works in regimes that are far from optimum mode. It means that specific fuel consumption is high. Some examples of measured operational regimes of locomotives in shunting operation and other motive power units are given in the paper. Kinetic energy of a classic diesel locomotive as well as the DMUs and trains is transformed into thermal energy during braking process. Normally it is not possible to utilize this kinetic energy in areasonable way. In order to improve fuel economy, the kinetic energy should be transformed into a suitable form and stored for subsequent use. The improvement can be achieved by using of the unconventional traction drive of rail vehicles. One of possible ways is using of the hybrid traction drive. The hybrid drive includes the ICE, generator, traction motors and the energy storage device. In this case the output of ICE can be substantially lower than in the classic traction. The parameters of such traction drive must be based on analysis of real operational regimes of vehicles. Those parameters are particularly: output of ICE,output of traction motors, capacity and output of energy storage devices (accumulators). There are other ways how to save fuel on railway vehicles, e.g. by better utilization of heat released from the fuel or using of solar energy