This is a signal crossing control system (a signal such as a red light, for example), which comprises three parts:

Signal Crossing Prevention System (Automatic Train Stop) : KFS SIL2 system

This is a signal crossing control system (a signal such as a red light, for example), which comprises three parts: a KSF1 beacon installed on the track in interface with the signals, an onboard sensor, fixed on the truck, which receives data from the beacon and finally an onboard calculator has the task of sending the data from the sensor and issues an emergency stop command to the train.

Documents and ISA* Certification


>  KFS SIL2 System



> KFS on Rhônexpress
> www.daat-sil2.fr

*Independent Safety Assessor

Operating principles of the KFS SIL2 (ATS)

KFS SIL2 is an Automatic Train Stop (ATS), developped by CLEARSY. The KFS system operates from three elements:

> an onboard KFS sensor
> a KFSI beacon installed on the ground on the track
> an onboard KFS processing block or rack

> The principle behind it is simple: the onboard KFS sensor detects an electro-magnetic (or magnetic) field, emitted by a KFSI beacon, installed on the ballast between the running rails via the intermediary of an external chassis, and relayed to the manoeuvre protection signal. The KFS sensor sends the information picked up at the KFS processing block, which is responsible for decoding it and passing on the information for the emergency braking or the driver’s alarm, which in turn triggers the halting of the tramway.

> The KFS system is compatible with the KPVA beacons. When those beacons detect an unexpected high speed, they send a signal to the KFS sensor that is installed on the train. The KFS controller immediately trigger an emergency braking.

> CLEARSY proposes to install a sensor at the end of the factory line in order to detect potential remaining pieces, that may damage or tear the KFS and KPVA beacons that are set up on the tracks.


1- KFS (anti-signal crossing) Sensor
> Its main objective is to detect two types of fields: one is magnetic from an electric magnet or permanent magnet, the other is low frequency electromagnetic from an antenna, generated by the RPS, KPVA or KFS1 Beacons assembled on the track between the train rails. The KFS sensor sends the information it receives to the KFS block, which decodes it and transmits the information to the emergency brake system or the driver’s alarm.

2 – KFS (Signal Crossing Prevention) Block or Rack
The KFS block is an onboard ; its main objective is to:
> Decode information from the magnetic onboard KFS sensor, which is generated by the RPS, KPVA or KFSI Beacon installed on the track between the train’s rails,
> And transmit the information to the emergency braking system (VACMA).
The KFS block receives two types of electrical signals from the magnetic sensor:


The analogical KFSI Beacon is an integrated autonomous system for electrical and thermal railway systems (train/urban subways/RER/tramway).Its main function is to provide information on a crossing at a traffic signal (red light/green light)



> CORSE : Year implemented 2006 – Number of copies: 35
> RHÔNEXPRESS : Year implemented 2010
Number of copies: 11 balises KFSI SIL2, 7 capteurs et racks. Installation : Vossloh
> VALENCIENNES TRAMWAY: Year implemented 2014
Number of copies: 28 balises KFSI SIL2, 28 capteurs et racks – Installation : INEO.
> NICE: Year implemented 2019
Number of copies: 22 balises KFSI SIL2, 58 capteurs et racks –