Online contact line measuring system OVHWizard for monitoring the contact line position during travel.

The OVHWizard is 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 the advantage over optical systems that it also works in direct sunlight, light rainfall or fog. Thanks to its weight of only about 8.5 lbs 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 which was developed in co-operation with SIEMENS AG allows the measured data to be compared with the given line data and types of catenary.

The system is approved by the DB, the SBB, the ÖBB and Network rail.

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OVH Wizard Contact Wire Position Measuring System

Requirements of the online contact wire measurement

Mobile, non contact measuring system for detection of the contact wire pos­ition

For the safe use electrified railway tracks – as well in the rail area as in tram area – is the observance of the exact contact wire vital relevant. This applies especially for 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.

The OVHWizard System

Two specially developed high perfor mance ultrasonic distance sensors form the core of the OHVWizardcontact 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 on

Measuring principle and system concept

The OVHWizard measures the distance by means of 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. The measured data are picked up in synchronisation with the line kilometering, triggered by pulses from a distance sensor.

The OVHWizard can be used on

  • Road rail vehicles
  • Contact wire laying vehicles
  • Measuring trolleys
  • Measuring trains
  • Rail laying machines

​​Vehicle Compensation

By mounting the OVHWizard, the measurement of the contact wire position in relation to the top edge and centre of the rail is influenced directly by the movement of the measuring vehicle.

The measurement can be made without compensating these errors when moving very slowly (up to approx. 10 km/h) or when the demands on the measuring accuracy are low.

For high precision measurements when the vehicle is moving the OVHWizard offers compensation inputs for the vertical (suspension) and horizontal (track clearance) movement of the vehicle as well as for the rolling angle around a known centre of rotation. Compensation takes place directly in the measuring system.

Data Output


If the vehicles on which the OVHWizard is to be used already have vehicle compensation, all the measured data of the contact wire position with distance and time reference can be transferred to this system via TCP/IP.


PC Software


The software which runs on all Windows systems enables both measured data entry and online display and a comprehensive post processing after completion of the measurement in addition to 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 Data


Measurement Accuracy                        + – 5/64 in
Measurements                                       23 measurements per second
Height Range                                          3 9/32 ft to + 13 1/8 ft
Stagger Range                                        ± 19 11/16 in
Wires/Cable                                            2 at any 1 time
Vehicle Speed                                        0 to +80 MPH
Battery NiMh                                          8 hours ~
Beam Weight                                         10LB (4.5KG)