Find out more about train protection at SBB and the three systems used for this in Switzerland.
SBB operates the most heavily and densely used rail network in the world. Every day, several thousand trains run on SBB’s network of over 3,000 kilometres, delivering around one million passengers to their destinations. SBB also transports over 100,000 tonnes of freight on its rails each day.
Train protection plays an important role in ensuring that passenger and freight trains run safely and on time over this busy network.
A train protection system for the whole of Europe.
There are a large number of different national train protection systems in Europe for historic reasons. For a train to be able to run from Rotterdam to Genoa, it currently still requires several different train protection systems. ETCS (European Train Control System) was developed as a European standard to harmonise technologies and promote rail transport in Europe, thereby strengthening the competitive advantage of rail transport.
The large number of train protection systems used in European countries is to be replaced by a technologically and operationally standardised solution to facilitate frequent and fast cross-border train movements throughout Europe.
With the rollout of ETCS Level 1 completed in 2018, Switzerland is the first country in Europe to fully meet the requirements for European interoperability.
Thanks to the network-wide use of ETCS Level 1 and Level 2, the entire Swiss standard-gauge network can now be operated without the use of an additional national train protection system.
In ETCS Level 1, the locomotive driver drives according to lineside signalling. Additional information is displayed in driver’s cab.
The fixed signalling system with national signalling and track-release system remains in place. The signal aspects are picked up from the track-side signals via signal adapters and telegram coders (LEU - lineside electronics units) and transmitted as a movement authority with route data to the vehicle at fixed points via Eurobalise beacons. The on-board computer continuously monitors and calculates the maximum speed and the braking curve from this data.
Because of the spot transmission of data, the train must travel over the Eurobalise to obtain the next movement authority. With the installation of a Euroloop between the distant signal and main signal, the new signal aspect is transmitted continuously. The Euroloop is an extension of the Eurobalise over a particular distance that allows data to be transmitted continuously to the vehicle over a cable emitting electromagnetic waves.
ETCS Level 2 is a radio-based train protection system. Movement authority is displayed via cab signalling. Besides a few indicator panels, lineside signalling is not required.
Train detection and, therefore, train integrity supervision still remain in place at the track-side. All trains automatically report their exact position and direction of travel to the radio block centre (RBC) at regular intervals over the GSM-R network. The movements of the trains are monitored by the radio block centre. The movement authority is continuously transmitted to the vehicle from the RBC via the GSM-R network.
The Eurobalises are used as passive positioning beacons (electronic kilometre markers). Between two position beacons, the train determines its position through sensors (axle transducers, accelerometers and radar). The positioning beacons serve as reference points to correct any distance measurement errors. The on-board computer continuously monitors the transmitted data and the maximum permissible speed.
In Switzerland, a distinction is made for ETCS Level 2 between conventional speed areas and advanced speed areas. The difference between the areas is that conventional speeds are those up to 160km/h and advanced speeds are those between 160km/h and 250km/h.
The ETCS Level 2 train protection system for advanced speed areas is used on the Rail 2000 Mattstetten–Rothrist route, in the Lötschberg Base Tunnel and in the Gotthard and Ceneri Base Tunnels. ETCS Level 2 for conventional speed areas is used, for example, on the Brunnen–Altdorf, Biasca–Castione, Lausanne–Villeneuve or Sion–Sierre routes.
With Level 3, ETCS goes beyond pure train protection functionality. In addition to the cab signalling detailed in ETCS Level 2, train-spacing is carried out using moving blocks.
Fixed train detection devices (GFM) are no longer required. As with ETCS Level 2, the trains locate themselves by means of positioning beacons and sensors (axle transducers, accelerometers and radar) and must also have on-board capacity to determine train integrity to the highest degree of reliability. By transmitting the positioning signal to the radio block centre, it is possible to determine at any time the point of the route which this train has already passed. A further movement authority for this point can then be granted to the following train. The route is therefore no longer cleared in fixed track section intervals, but using changeable intervals called moving blocks.
ETCS Level 3 departs from the classic operation with fixed intervals. With sufficiently short positioning intervals, continuous line-clear authorisation can be achieved. The spacing of trains follows the principle of driving in braking distance spacing.
The long-term objective is to develop the current systems in the direction of ETCS L3.
