Automatic train protection

CAS-E system controls and coordinates the position and speed of the rolling stock, protecting them against collisions due to undesirable operational situations with the rest of the traffic and preventing them from achieving conflicting routes or hazard situations.

Suitable for main tracks, stations, shunting and depot areas, the CAS-E system comprises on-board, outdoor and indoor equipment. Designed to be compatible with elevated viaducts, underground tunnels or at street level, its track-side equipment is totally independent and decoupled from the rails, providing a transversal solution for Trams, Monorails and Rubber-Wheel Rolling Stock.

• Automatic Train Protection (ATP) – SIL-2 / SIL-4 architecture
  • Speed Supervision: When the CAS-E system is turned on, the speed is obtained from the speed sensors and is continuously analyzed by the onboard process unit, supervising the entire line, so that the tram does not exceed the maximum speed allowed. When the rolling stock passes over an emitter beacon, the onboard equipment receives the speed conditions for the track ahead and calculates the braking curves to reach the target point with the required target speed in safety conditions

• • Signal Pass at Danger (SPAD): To prevent trams from passing stop signals, emitter beacons are strategically installed:
    Previous beacon: Located at braking distance from the signal, it instructs onboard equipment to stop if the signal shows a stop aspect, calculating braking curves for safety operation. In case of exceeding speed limits, the CAS-E system acts by three programmable action levels or allows maximum speed if the signal is permissive.
    Signal beacon: Positioned just before the signal at emergency braking distance, it immediately commands braking if the signal shows a stop aspect by activating maximum service brakes and tram safety brakes if necessary, or sends a “go” command if the signal is permissive. Signal aspects are communicated via the interlocking system through the beacon controller’s I/O interface.

• Rolling stock detection ECB – SIL-3 architecture: The CAS-E system provides a state-of-the-art detection system using safe radiofrequency communication between the rolling stock and track-side equipment. CAS-E does not require, although it is compatible, the use of classic track circuits or axle counters which are not suitable anymore in urban environments where new requirements such as the esthetic of the installation, low level of maintenance and high availability. The system uses receiving beacons on the ground to detect the passage of rolling stock by receiving radio frequency messages continuously emitted by on-board antennas located under the driving cabins. As a result, the beacon controller can transmit to the interlocking when the head and the back of the rolling stock are just getting the point and determining its position on the track.

• Route request: In the CAS-E system, route requests straight, right and left can be sent via onboard pushbuttons by the driver or automatically by the Traffic Management System (TMS). These requests, continuously transmitted by the onboard CAS-E equipment’s antenna, specify the desired route within a 10-second or 100-meter window. If no specific request is made, a default “Not pressed” request is transmitted. A receiver beacon located before a switching point receives these messages and transmits them to a beacon controller, which communicates with the interlocking and blocks the route if the safety conditions allow it.
• Auxiliary functionalities: Beacon linking, temporary speed restrictions, TMS location refresh, anti-rollback, doors management, events and alarms recording.

• On-board equipment: Comprehends a processing unit and an antenna at each rolling stock cabin and two dual-channel speed sensors.

• Field equipment: It consists of beacons installed along the line. These beacons can transmit data (emitter beacons) or receive it (receiver beacons), according to its functionality.

• In-door equipment: It consists of a standard 19” subrack with electronic boards (CPU, safety input/outputs, etc.) called Beacon Controller in charge of controlling the entire set of beacons which allows communications with third-party interlocking by inputs/outputs or safety protocols based in EULYNX SCI_IO. If the signalling system is controlled by ENCETRANS 2oo2 interlocking, the functionalities of the Beacon Controller will be integrated into the interlocking itself.