Gears are the main elements of transmission mechanisms such as reducers for general industrial applications, gearboxes of land transport vehicles and railway reduction gearboxes. They all are subjected to substantial dynamic loading and wear during operation. This paper analyses the materials used to produce various types of reducers. The main wear processes are examined in compliance to DIN 50320. The presented heat treatment technologies are aimed to achieve the best indicators determining the workability, contact strength and bending strength of materials. Measurements of gear profiles made of different materials and intended for a railway vehicle (electric locomotive) have been done. A formula for predicting the wear of gear profiles has been worked out in a probabilistic aspect. Optimised approaches to extend the service life of gears are suggested. It is also proposed what type of materials and technologies to choose for heat treatment of the selected reducer gears.