Switches and crossings

The first mobile switch service was established in 1992 by switch manufacturer Vossloh Laeis. The founders of that time are now working for Rhomberg Sersa Vossloh GmbH (RSV).

Professional switch maintenance requires specialist knowledge for which there is hardly any literature outside the regulations of the state railways. With the founding of BahnWege-Seminare® in 1994, switch technology was made accessible to a wider audience with the help of specialists, such as Günter Welz, who have mastered both manufacturing and maintenance. 

For today's Rhomberg Sersa Vossloh GmbH, specialised switch maintenance is one of the core tasks. With teams of two mechanics and electricians, the company is able to carry out all work on switches.This holistic maintenance from a single source minimises interfaces and waiting times, as work can be carried out independently of other trades. 

Complex and intricate switch systems occupy a special position, including crossing switches (see box). Knowledge of this resembles a kind of secret science. A need for this arose at a construction site on Lake Constance:

Problems were caused in November 2019 by a double slip switch installed by Rhomberg Gleisbau / Bahnbau Wels in Lindau. For five of the eight switch rails, it was not possible to establish a safe end position on the stock rails and studs because they had a high residual voltage. Due to the resulting narrowing of the gauge, acceptance and operational release were not possible. 

RSV was asked for rapid support: our switch specialist Günter Welz, who has more than 40 years of experience in the production and maintenance of switches, went to the site as quickly as possible. His analysis brought the causes to light and enabled a targeted correction of the double slip switch (DSS) with outside switches. A switch shape that you don't see every day. 

At Welz's suggestion, three of the short switches of these DSSs were mechanically separated and then fixed in such a way that they fit correctly on the stock rails and switch supports. The switches were reconnected to the adjoining rails by means of flux-cored wire welding. Now the reinstalled switches were able to be straightened hydraulically without tension. Günter Welz was able to align the two remaining problem switches without separating the welded joints and also correct the faulty check blocks and studs by grinding, so that the switch support on the stock rails and the track gauges were permanently corrected. 

Thanks to RSV's expertise, the selection and implementation of the measures led to immediate success. The special approach also generated lively interest on the part of the client, Deutsche Bahn AG, who had anticipated the need to replace the faulty components, which would have meant enormous economic damage in terms of costs and availability.

Slip switches are a combination of a crossing and a switch. Unlike simple crossings, they can be used to change from the crossing track to the crossed track. If this is only possible in one direction, it is called a single slip switch. A double slip switch allows changing in both directions. In both single and double slip switches, the switches can be found inside or outside the crossing quadrilateral.