Contact Line Measuring System (OVHWizard)

The OVHWizard is a non-tactile contact line measuring system for determining the contact line height and stagger with and without uplift.

Contact Line Measuring System (OVHWizard)

ADOR Tech, with the help of its international partners, design, and manufactures the OVHWizard that a non-tactile contact line measuring system for determining the contact line height and stagger with and without uplift. The system operates with ultrasound according to the runtime measurement principle.

This measuring principle offers an advantage over optical systems in that it also works in direct sunlight, light rainfall, or fog. Thanks to its weight of only about 4 kg, it is easy to handle and can be installed on any vehicle roof with a few actions. A simple RS232 link to the PC or laptop enables communication with the measuring software. 

A special evaluation software that was developed in cooperation with SIEMENS AG allows the measured data to be compared with the line data and types of catenary. The system is approved by the DB, the SBB, the ÖBB Network rail, and the Turkish Railways TCCD.

The OVHWizard can be used on:

  • road-rail vehicles
  • contact wire laying vehicles
  • measuring trolleys
  • measuring trains
  • rail laying machines

At ADOR, as Dr. D. Wehrhahn's representative in Canada, we have integrated our engineering and commercial expertise to provide customers with tailor-made solutions. We are ready to provide technical and engineering services for sophisticated and complex necessities of every inquiry based on the skills and experience of our staff, resources, and capacities. Get in touch to discuss your requirements!


To ensure the safe use of electrified railway-tracks-both on rails and on trams-it is essential to observe the exact contact wire. This applies especially to the modern high-speed line. Next to contact wire height and lateral position is the gradient between two masts and the length span, a criterion that always has to be controlled.


Two specially developed high-performance ultrasonic distance sensors form the core of the OHVWizard contact wire position measuring system. These sensors are installed respectively at an optimum angle at the ends of the measuring instrument.

The entire processing electronics are located in the connecting tube between the sensors. The system is battery-operated and can therefore be used in every vehicle.


OVHWizard measures the distance by ultrasound and the pulse-echo method, i.e., a sonar pulse transmitted by the sensor is reflected by the contact wire and back to the sensor. The time which elapses (runtime) is proportional to the distance.

The exact contact wire position is given by the point of intersection of the two distance sensors. measured data are picked up in synchronization with the line kilo metering, triggered by pulses from a distance sensor.


The non-contact wire position measuring system OVHWizard detects the height and stagger of the contact wire in relation to the installation site of the measuring system. This is 3-4 m above the top of the rail on the roof of the vehicle or to a holder of an appropriate height.

The movements of the vehicle on the track while driving affect the measured value more or less according to the suspension. To compensate for this impact, the movements of the vehicle will be compensated either by 5 ultrasonic sensors or 2 laser scanning sensors in a horizontal direction (gauge clearance), in the vertical direction (height movement), and the rolling of the vehicle (rotation of the superstructure to the vehicle axis of rotation).

Both systems generate compensation which that is forwarded directly to the contact wire measuring system OVHWizard. In the OVHWizard, the actual measuring values will be corrected online with the compensation data.


From the 5 ultrasonic sensors, two sensors detect the horizontal movement in the track, two additional sensors detect the height movement and the rolling motion of the vehicle. The fifth sensor is used to compensate for the temperature dependence of the ultrasonic measurement.


The two sheets of light sensors detect the complete rail profile until above the running surface. With a vehicle movement in the track, the position of the rail relative to the sensors is shifted or twists. From this change in position, the software determines the three vehicle movements’ height and lateral position and the rolling of the vehicle.


The software which runs on all Windows systems enables both measured data entry and online display and comprehensive post-processing after completion of the measurement, besides the creation of the measuring profiles for the vehicle setup. The following standard evaluations are possible:

  • tolerance monitoring for side and height
  • display of overlaps
  • height of the contact wire
  • height of the support cable
  • stagger of the contact wire
  • stagger of the support cable
  • determination of the mast distance
  • determination of the gradient
  • detection of line events (signals, crossings, points etc.)
  • compensation of the vehicle position
  • table printout
  • video surveillance of the contact wire (optional)


Technical Details

Listed below are the general technical specifications of our Contact Line Measuring System (OVHWizard). For the complete specifications in details, please download the catalog at the bottom of the page.

accuracy: ± 2mm

Measurements: 23 measurements per second

Vehicle speed: 0 bis 80km/h

Battery NiMh: app. 8 hours

Weight: app. 4.5 kg


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