Automatic Track Warning Systems (ATWS) use devices called treadles attached to the running rails to automatically detect the wheel bogie of passing trains. Treadles are positioned at appropriate mileages to provide the required warning time to track-workers of an approaching train. Additionally treadles are used to automatically cancel the warning automatically when the train leaves the worksite.

Schweizer Electronic provides rental of a full range of MINIMEL95 ATWS and LOWS to approved partners. All our equipment is maintained and regularly inspected by our HQ in Switzerland.

Our UK partners provide a full service to Network Rail and its contractors including operation, installation and planning of MINIMEL95 ATWS and LOWS.

The main benefits of ATWS for temporary worksites include:

  • Automatic detection and warning of trains, safer than lookouts
  • Better track access and workgroup productivity
  • A reduction in protection staff
  • Enables work on live running rail or near an adjacent open line

How does ATWS work?


Mechanical or induction ‘Skrike-in’ treadles placed at appropriate sighting distances are used to detect the wheel boogie of the train, and installed on all approaching roads to the worksite. Once activated the warning signal is sent via cable or radio (using an EKF) to the worksite. 


The control unit (called a ZE) receives processes signals from the treadles and passes a warning to either cabled rotating lamps and horns for the whole worksite, or individual radiographic warning devices (called EWK’s) for each COSS and workgroup (using a transmitter called an EZE).


Further treadles are used to monitor the train path through crossovers and signaling, finally cancelling out the warning automatically once the train has left the worksite.

Schweizer Electronic’s ATWS Systems:

Videos - Minimel Lynx

Videos - ATWS Minimel 95

ATWS Case Studies