Wheelshunt Detector HAP II

Detecting vehicles, determining positions, securing routes - HANNING & KAHL systems for vehicle detection make sure you have all these processes safely under control. In compliance with different project requirements, HANNING & KAHL deploys various proprietary systems to secure routes and for passive detection of rail vehicles.

Track circuit for detection of wheelshunt: while its axles produce a short circuit (< 0.3 Ohm, max.5uH) in the track area, the rail vehicle is reliably detected by the electronic system.

Blocking circuit for detection of the combination of wheelshunt and vehicle mass:
The Blocking circuit recognises entry of the rail vehicle passively by the wheelshunt (< 1 Ohm, max. 5uH) produced and vehicle exit by the diminishing vehicle mass detected.

In both detection procedures, a wheelshunt of < 0.3 Ohm or  < 1 Ohm is necessary. This wheelshunt results from the sum of the contact resistances of the line: rail –> wheel tyre –> axle –> wheel tyre –> rail. Vehicles should be maintained regularly to ensure proper wheelshunt.

However, checking/verifying wheelshunt and wheel rail contact on a vehicle can often be difficult. Individual punctual measurements on a wheel tyre are not effective in this case because the wheelshunt must be maintained on the rail over the passing wheel for the entire length of the track or blocking circuit.

HANNING & KAHL’s wheelshunt detector HAP II can solve this problem. Composition consists of a test track circuit, the length of which is to be calculated in such a way that the axle of one bogie leaves the test track circuit before the next axle crosses the segment. In the measurement segment, a HFP detector stage especially designed for the test track circuit continuously determines the wheel rail contact, the resulting frequency and amplitude distortion.

After the crossing by the rail vehicle, each axle is subjected to qualitative assessment by the HAP II. Speed influences on the crossing of the test track are allowed for by determination of the actual speed on the axle counters. The evaluation software carries out a qualitative evaluation of the axle on the basis of a tolerance range specified by the user. The easiest way is to use a PC-based traffic light diagram (red-yellow-green), or signals in the outside area which visualize the status of the individual axles to the rail vehicle driver. With interfaces to a depot management system digital vehicle protocols can be compiled and administered.

To achieve high process safety and to also ensure the quality of the measurement in the long term, operating resources are available for maintenance purposes.