A rail brush assembly for an electric motor having a commutator, comprises a brush, a spring, a pair of rails and at least one detent for retaining the brush on the rails. The brush has a groove on each of a pair of opposite sides. The rails are disposed in the grooves for guiding the brush to the commutator with the brush being freely slidable along the rails within a predetermined range of motion. The spring is arranged to urge the brush along the rails towards the commutator of the motor and is attached to an end of the brush remote from the commutator. The detent is formed between the spring and at least one rail to limit the range of movement of the brush along the rails.