Railways simply explained
Block force measuring: Wafer-thin film revolutionises brake safety.
18. 06. 2025
Safe rail operations can only be guaranteed if all brakes function reliably. The block force measuring plays a key role here. It measures the actual braking force on vehicles with so-called block brakes - where a block is pressed directly against the wheel during the braking process. The latest generation of the monitoring device now delivers much more accurate data and, for the first time, does not require any intervention in the complex braking systems to make a measurement. This significantly reduces sources of error.
The classic check with the block force measuring: quite time-consuming
In the past, the braking force on freight wagons was checked rather indirectly. The usual method was to measure the pressure in the brake cylinder - and assume that this transmitted sufficient force to the brake blocks. But this was precisely the problem: there is a complex linkage with pivots, bushes and bolts between the brake cylinder and the wheel. These connections wear out over time, lubricants are lost, friction increases - and efficiency decreases.
This meant that although the brake cylinder pressure was correct at the time of the check, significantly less braking force was applied to the wheel - a dangerous safety risk. If you wanted to measure the actual force, you had to use a load cell. This involved removing the brake block and installing the load cell - an intervention that also altered the closed system and could affect the measurement result.
The new solution: Measuring with tablet without any intervention
The new generation of the block force measuring uses 0.5 mm-thick sensor foils that are inserted between the brake block and the wheel. Despite their thinness, they are stable and durable. The measurement is controlled via a mobile module with tablet, compressed air sensor and up to 24 force measurement foils. The real air pressure in the system is taken into account, calculated and the mechanical efficiency of the braking system precisely determined.
A digital log shows in real time which brake calliper is transmitting how much force and where. Weaknesses are immediately detected and documented. The special feature: The brake system does not need to be modified for this. This eliminates the risk of measuring a different behavior than in real operation by installing a measuring device.
With our new measuring system, we are replacing an assumed safety factor with an actual one - enabling us to obtain braking values that can be traced, shared and viewed by everyone involved at all times.
Christian Gruböck, ÖBB TS
A practical example with big impact
Depending on the manufacturer, the brake components under the vehicle in the bogie usually have to be replaced every six years on freight wagons and railcars. This is a time-consuming and heavy process in which one unit can weigh over 100 kilos.
It took around five days to service a three-part set, including arrivals and departures. With the new system, the same safety check can be carried out in just four hours - without any dismantling. This saves time and money, while significantly increasing vehicle availability.
At least one general overhaul is saved over the entire life span and the wagons and locomotives can be put back into service much more quickly.
Conclusion: The new block force measuring eliminates the need for time-consuming and inaccurate brake force checks. It delivers precise, reproducible results quickly and safely, without the need for system intervention. The new system was introduced at ÖBB at the end of 2022 and is already in use in workshops such as those in Villach, Graz, Vienna and Linz, with more to follow.
