Wheel flange lubrication
The wheel flange lubrication or rail flank lubrication is used in rail vehicles to the wear of wheel flanges and rails and the noise to be reduced. This also minimizes the possibility of climbing .
In curves in particular, frictional forces arise between the wheel flange and the rail flank, which leads to wear. There is also a lot of noise, especially squeaking. To reduce this, a wheel flange lubricator can be used to apply lubricants to the wheel flanges or flanks of the rails , which reduce friction and thus also wear and tear and noise.
Applying the lubricant to the actual wheel or wheel tire tread must be avoided in order not to reduce the coefficient of friction between the rail and the railway wheel , which leads to a reduction in the tensile force and an extension of the braking distance. Grease contamination on the running surface of drive wheels can lead to skidding ("spinning") when starting or to sliding ("locking") when braking and cause flat spots on the wheel and skid spots (milled-out) in the rail.
For this purpose, many locomotives have an automatic device on the foremost wheel set in the direction of travel , which, depending on the design, applies grease to the wheel flange depending on time, distance or curve radius . A greasy paste is applied to the wheel flange using a pump or compressed air. In the simplest case, this is done purely mechanically, in that the turning of the bogie in relation to the locomotive frame in the curve actuates a pump, or it is path-controlled at regular intervals. Since the grease is distributed on the rail flanks, this also leads to lubrication of the following wheels. In the past, pieces of felt soaked with lubricant were also used, but they did not allow lubrication as optimized as controlled lubricating devices.
Especially on trams , but also on winding railway lines , the lubrication device can be attached to the rails so that a reduction in noise and wear is only achieved in a targeted manner in very tight curves.
As a side effect, near these track lubrication points on trams, the rail groove and the road surface are contaminated with deposits of grease and dust. Pedestrians who pay less attention to the road surface can make their shoes very dirty, particularly at rail lubrication points with overflowing grease. The risk of accidents for cyclists who drive over a lubricated grooved rail at an acute angle also increases.