Dr D Wehrhahn - Non-Contact Measuring Systems for the Railway Industry

Dr D Wehrhahn specialises in railway industry laser systems, including standard laser probes, specially developed customised sensors and complete measuring systems with laser, mechanics and software.

OPTImess laser sensors are a universal measuring instrument for railways due to their small size, high measuring frequency and accuracy, and their ability to measure under almost any ambient conditions.

Wheel profile measurement

The OPTImess compact, laser-based measuring instrument ensures that the profile data of wheels are selected and measured reliably. The measuring system is battery-operated with a data logger as an input and memory medium.

Measurements on the wheel and assessment of wear can be performed quickly and easily. The characteristic variables such as wheel flange thickness, wheel flange height, wheel flange width, flange angle and wheel gauge are measured.

Wheel set measuring stands

If only the characteristic variables of the wheel profile are determined in the application described above, the use of several sensors on a two or three-axle drive unit allows almost all parameters of the wheel set, such as profile, impact, brake disks, and flattening to be measured.

All parameters to be measured are determined, measured automatically and logged by entering the wheel set identification. The flexibility of the laser sensor in terms of dimensions, measuring distance and measuring range also allows the conversion or retrofitting of existing tactile measuring stands.

In-track wheel profile-measuring system

The OPTImess laser system is a new in-track measuring instrument for railway vehicles. Wheel diameter, back-to-back distance, flange gauge and wheel profile parameters for wheel flange thickness, wheel flange height SH and the qR dimension are measured at speeds up to 20km/h.

The entire profile of every wheel is available for evaluating the wear and optimising the profile. All data is saved in a database with the vehicle number, which is detected automatically by a transponder. In addition to analysis functions the software also offers a wear forecast for planning maintenance assignments.

RAILMONITOR - a world first in mobile rail measurement

The RAILMONITOR combines non-contact laser measuring technology with an integrated TFT screen and integrated computing software, for all the parameters required for grinding including comparison with standard profiles. Its total measuring time is less than 20s/profile.

Its measuring range and total construction allows Vignol, and grooved rails and points including tongues to be measured. The determined measuring curves are displayed immediately on the integrated TFT screen and saved on a CompactFlash card.

Rail profile measurement

To classify of the state of wear of the rail head, and evaluate the necessary maintenance work, measuring vehicles equipped with laser sensors, in which five to seven sensors per rail side are positioned around the rail head, are used. Measured values are recorded every 20cm at these points, at about 80mph, and compared with the nominal profile in the computer. The computer classifies the deviations according to given tolerance values.

Contact wire measurement

The OVHWizard mobile, non-tactile contact wire measuring system determines contact wire height and side position as well as an assessment of the tendency of the contact wire to wear. The system operates with ultrasound according to the principle of runtime measurement. Its weight of just 4kg makes it easy to handle and it can be installed on any vehicle roof in just a few simple steps. A simple RS232 connection to the PC or laptop enables communication with the measuring software.

Power is supplied to the OVHWizard by the integrated batteries so that no other power supply needs to be provided or wired for the measuring instrument on the vehicle roof.

A pulse transmitter consisting of a light barrier and a self-adhesive reflector for attaching to the wheel can be connected to the measuring system for determining the distance travelled. Pulse signals from a rotary encoder or similar on the vehicle can also be read in as a possible option.

The measured data is recorded by the enclosed software and displayed and saved graphically or in table form. The post-processing enables an exact evaluation of the measuring runs on site or at the office.

The system is suitable for recurrent control of the contact wire for railways and trams as well as for documentation of maintenance work.