Safely connecting Europe’s railways

The European Train Control System (ETCS) is a signalling and control system designed to replace the 14 incompatible safety systems currently used by European Railways, especially on high-speed lines.

This year, the UIC is holding its ERTMS World Conference in Berne, Switzerland. Switzerland offers a prime example of how ERTMS has been successfully integrated into national transport plans. Together with major railway civil engineering schemes, such as the impressive Lötschberg and Gotthard tunnels, the Swiss Administration is satisfied that ERTMS (ETCS + GSM-R) and the Traffic Management Layer will enable them to meet the strong domestic and international growth forecasts expected of rail in the near future.

Development history of ETCS

ETCS development is under installation in many European countries – either as pilot projects or early implementation projects. At present, there are a host of technical hurdles hindering the cross-border operation of rail traffic in a European network. One of the main reasons of this hindrance is the historical development of 14 mutually incompatible train control and train protection systems. To enable a better understanding of this reasoning, Deutsche Bahn (DB), Ferrovie dello Stato (FS) and Société Nationale des Chemins de fer Français (SNCF) together set-up the ERTMS Users Group in 1995 with the object of specifying ETCS as part of the ERTMS, testing it on trial routes and perfecting it for practical implementation. The Users Group now also includes Nederlandse Spoorwegen (NS), Red Nacional de los Ferrocarilles Españoles (RENFE) and Network Rail (UK Infrastructure).

Following many years of dedicated work by the railways and the industry, the first standardized European Rail Traffic Management System was successfully formulated – with funding help from the European Union – in a harmonized draft of the system specification for ETCS.

A landmark date occurred on 25 April 2000. The standardized partners (represented by the ERTMS Users Group, all participating railways in the UIC and Europe’s leading rail engineering companies grouped together in UNISIG), signed an outline agreement for the introduction of a standardized, interoperable train control and protection system (ERTMS specifications). In autumn 2000, the member states agreed to publish these precise specifications in the form of a Commission resolution, thus creating a provisional legal and planning framework. In an initial phase, the specification will be tested by the six railways of the ERTMS Users Group and then used for regular service after this consolidation phase.

The UNISIG group

The UNISIG group brings together the companies providing equipment compatible with the new European Rail Traffic Management System – ERTMS. This new signalling system is designed to enable railway interoperability. The member companies of UNISIG are currently Alstom, AnsaldoBreda, Bombardier, Alcatel, Siemens and Invensys. The members of the group therefore study the content of the technical standards of ERTMS, and ensure that all their products fully respect these standards and are compatible with each other.

Levels of ETCS

ETCS is divided up into different equipment and functional levels and the definition of the level depends on how the line route is equipped and the way in which information is transmitted to the train. Basically, the movement authority (also know as “permission to proceed”) and the corresponding route information are transmitted to the train and displayed for the driver in the cab (“cab signalling”). A vehicle fitted with complete ERTMS/ETCS equipment (EuroCab) and functionality can operate on any ETCS route without technical restrictions.

ETCS – Level 0

If an ETCS vehicle is used on a non-ETCS route, then this is known as Level 0. The trainbourne equipment monitors the train for maximum speed and the train driver observes the national trackside signals.

ETCS – Level 1

ETCS Level 1 is a cab signalling system that can be superimposed on the existing signalling system. “Eurobalise” radio beacons pick up signal aspects from the trackside signals via signal adapters and telegram coders (LEU) and then transmit them to the vehicle as a movement authority, together with route data at fixed points. 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 has to first travel over the Eurobalise beacon in order to obtain the next movement authority. With the installation of additional Eurobalises (“infill balises”) or a EuroLoop between the distant signal and main signal, the new proceed aspect is transmitted continuously. The EuroLoop is an extension of the Eurobalise over a particular distance which basically allows data to be transmitted continuously to the vehicle over cables emitting electrical radiation.

ETCS – Level 2

ETCS Level 2 is a digital radio-based signal and train protection system. Movement authority and other signal aspects are displayed in the cab for the driver. Apart from a few indicator panels, it is therefore possible to dispense with trackside signalling. However, the track-release signalling and hence the train integrity supervision still remain in place at the trackside. All trains automatically report their exact position and direction of travel to the Radio Block Centre (RBC) at regular intervals. Train movements are monitored continuously by the RBC. The movement authority is transmitted to the vehicle continuously via GSM-R together with speed information and route data. The Eurobalises are used at this level as passive positioning beacons or “electronic milestones”. Between two positioning beacons the train determines its position via sensors (axle transducers, accelerometer and radar). The positioning beacons are used in this case as reference points for correcting distance measurement errors. The on-board computer continuously monitors the transferred data and the maximum permissible speed.

ETCS – Level 3

In Level 3, ETCS goes beyond the pure train protection functionality with the implementation of full radio-based train spacing. Fixed track-release signalling devices (GFM) are no longer required. As in ETCS Level 2, trains find their position themselves by means of positioning beacons and via sensors (axle transducers, accelerometer and radar) and must also be capable of determining train integrity on-board to the very highest degree of reliability. By transmitting the positioning signal to the RBC, it is always possible to determine which point on the route the train has safely cleared. The following train can already be granted another movement authority up to this point. The route is thus no longer cleared in fixed track sections and in this respect, ETCS Level 3 departs from classic operation with fixed intervals. Given sufficiently short positioning intervals, continuous line-clear authorisation is achieved and train headways come close to the principle of operation with absolute braking distance spacing (“moving block”). Level 3 is currently under development and solutions for reliable train integrity supervision are highly complex and are hardly suitable for transfer to older models of freight rolling stock.

ETCS across Europe

Introduction of ETCS varies considerably from country to country and depends on the present state of the protection system, the traffic density, the degree of rationalisation, the percentage of cross-border traffic and the financial situation.

Switzerland progress

Since 18 March 2007, ETCS has been fully operational on Swizterland’s railway network. This is a Level 2 application and the SBB are the first railway in the world to successfully introduce a highest density mixed traffic operation by applying ETCS Level 2 and GSM-R voice. The newly built Mattstetten-Rothrist line between Bern and Zurich is the core of the Rail 2000 concept.

Swedish progress

Sweden has ETCS Level 2 operational on 190km of the Botnia line and has an ERTMS-Regional pilot line on the route from Repbäcken-Malung.

High-Speed networking

In Spain, Italy and the Netherlands, ETCS Level 2 is being implemented predominately on high-speed routes which in most cases are newly constructed lines. ETCS is partially superimposed on the existing national system, either as parallel signalling or as a contingency. Level 2 is being implemented for Spain on the high-speed lines Madrid-Barcelona, Madrid-Segovia Valladolid, Cordoba-Malaga and Madrid-Valencia. ETCS Level 2 is being implemented on the new high-speed lines Rome-Naples, Florence-Bologna-Milan and Milan-Turin. The Netherlands holds some important ETCS projects. Level 2 is running on new lines including the high-speed line south (Amsterdam-Rotterdam-Belgian border), the Betuwe freight line and the new double track line from Amsterdam-Utrecht.

Interoperability focus

ETCS Level 1 is expected to be implemented on the entire core network on Belgium and Luxembourg within the next 10 years – parallel to the present national system. Belgium has Level 2 ETCS on the new high-speed lines from Antwerp-the Dutch border and Liege-to the German border.

Focus on replacement

Austria, Hungary, Romania and Bulgaria all have a level of ETCS in common. Level 1 is being introduced in order to close the existing safety loopholes and/or replace the national protection system.

Corridor focus

In Germany and France, ETCS is being introduced primarily on the high-speed and freight corridor routes by superimposing it on the national system. The existing LZB and TVM systems are to be replaced by ETCS in the long-term.