Obstructions in Lower Clearance

Measurement of clearance using leaf springs is a particularly economical means of clearance measurement. The leaf springs are placed at the height of the brake discs and serve to measure the cladding height at the outer edge of the rails. If clearance is short in this zone, the leaf springs are bent and the resistance value of the potentiometer thus changed. The height at which the springs are positioned is matched to the object being tested - e.g. the brake discs - to determine where these come into contact with the cladding and are damaged. These points are calculated using the evaluation software and can be easily matched to the parameters captured:

  • Position on the route (GPS coordinates and route)
  • Speed.

Version with Spring Flaps:

When measuring bottom clearance with spring flaps, the entire clearance under the vehicle and and along the outer side of both rails.


Following periods of frost, roads and paths - often built using paving blocks - are subject to vertical deformations that can interfere with the passage of rail vehicles. Testing with spring flaps is an effective means of detecting these points without excessive outlay.

The measurement run can be performed using standard rolling stock during normal daily service. The outcome will be obtained immediately - whether the clearance has been compromised or not.


Data from the potentiometer is captured and displayed clearly in an ADC (analogue-digital conversion) chart. Loss of clearance is indicated in proportion to the intensity of the ADC value.

The evaluation software enables the user to display these results quickly in a map view and in a list or .kml file, or to export the data for other purposes.

Measurement system images



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