Schweizer Electronic’s Signal Controlled Warning Systems (SCWS) offers a permanent safety solution for sections of the railway infrastructure. SCWS helps maximise rail network availability, while at the same time ensuring that track personnel receive reliable and automatic train warnings when accessing the track.

The main benefits of Signal Controlled Warning System include:

  • Modular concept, can be scaled to protect individual worksites or the entire network
  • 24/7/365 access to complex track and S&C
  • Requires no protection staff for regular maintenance activities
  • Self-diagnostics mean system can remain on permanently with no system start up required

How does it work?

Train detection:

Read feed from signal interlocking provides train movement information (position and direction of trains, position of points, status of train signals)


The central ISP unit calculates the appropriate warning time tailored to site conditions.

The central ISP is capable of working with solid state or relay interlocking systems, and can integrate with the latest standards in signalling technology such as ETCS (European Train Control System) and ERTMS (European Rail Traffic Management System).


Warning data transmitted to controller on individual worksites via landline, radio or GSM-R links. Alerts given to track workers via fixed lights and horns, or outputted to other other warning devices in the Minimel 95 and Minimel Lynx family, such as the Single Radio Warning Unit (EWK or EWK-L) or Personal Warning Unit (EPW).

SCWS Case Studies