Transporting passengers requires the highest levels of safety. Among the most sensitive areas for safety in buses and trains is boarding and disembarking. The world's leading manufacturers of rolling stock – Alstom, Bombardier, Siemens, Stadler and Deutsche Bundesbahn – therefore rely on Sitron's SITRANS alpha light grid system for improved safety at doors.

Automatic door monitoring

One of the highest priorities for the Deutsche Bahn is the safety of its passengers. The company pays particular attention to making boarding and disembarking – the most sensitive areas in passenger transport – hazard free. Only reliable systems that meet the highest standards are therefore used. Accordingly, the Bahn uses the latest, tried and tested technologies in automated door monitoring.

For this reason, market leaders in rolling stock construction and the Deutsche Bahn use SITRANS alpha light grids from Sitron to further improve safety in boarding and disembarking.

The rolling stock manufacturers and the Deutsche Bahn opted for SITRANS alpha because Sitron specialises in making reliable products for extreme ambient conditions. A further major requirement was the individual adaptability of light grids within carriages. Sitron was able to apply its many years of experience in developing specialist products for transport engineering.

The sensors were first used in the "Silver Arrows", the modern Stadtbahn light rail trains used by Hanover's public transport company ÜSTRA. The sensors underwent systematic, continuous development and optimisation to further improve safety standards. Sitron are leading experts also because they communicate directly with the rail operators.

Safe boarding and disembarking

Most accidents when transporting passengers occur during boarding and disembarking. Safety during the boarding and disembarking phases therefore has the highest priority. Doors are to open safely and, most importantly, need to close safely. They must also be highly sensitive to sudden and unexpected boarding or disembarkation as well as to objects being left in the door area after passengers have exited. For example, an umbrella jammed in a closed door can lead to an accident – the elderly and the disabled are especially at risk here. The SITRANS alpha light grid is also used in buses to provide hazard-free boarding and disembarking.
Around the world – from Australia to Switzerland – approximately 50,000 sensors have been installed in trains and buses because the SITRANS alpha system offers door safety under extreme conditions. A light grid must also function in cold and snowy climates such as in Switzerland. The system should also be unaffected by strongly fluctuating temperatures, e.g. in air-conditioned buses in Dubai. Under such conditions, a mini climate change occurs when doors open and close. This presents a major challenge to the light grid. But here too, trust has been placed in the reliability of the SITRANS alpha system.

With its SITRANS alpha product, Sitron provides a highly developed light grid system for the highest levels of safety in passenger transport.


Sitron Sensor GmbH
Nickelstr. 4
30916 Isernhagen

Phone: +49 511 728 50-0
Fax: +49 511 728 50-33
E-Mail: office(at)

On-site point of contact

You can find your personal Sitron customer consultant here.