What is ERTMS/ETCS ?

Introduction

ERTMS is the European Railway Traffic Management System that was developed and specified by the European signalling suppliers (UNISIG), European Railways and the GSM-R industry acting together under the guidance of the EC.   The major members of UNISIG are Alstom Transport, Ansaldo STS, Bombardier Transportation, Invensys Rail Group, Siemens Mobility and Thales.
 
Background

Over the year, over 20 different train control systems (TBL, EBICAB, INDUSI, KVB, LZB, TVM, ATB, etc) have been developed and operated by individual European Railways according to their national requirements on technical standards and operating rules.  However, the diversity does not meet the long-term reliability and efficiency requirements.  The automatic train protection (ATP) systems in use are non-compatible.  A train must be equipped with different ATP systems as it travels along different lines across the country borders.  Sometimes, it even requires changing locomotive or driver at frontiers as each country generally has its own signalling system for which the drivers have to be trained. 

The additional ATP systems take up a lot of space on-board.  It also adds to travel time, operational and maintenance costs.  Unifying the multiple signalling systems will provide better interoperability of freight and passenger rail services, minimise technical and cultural problems of cross-border rail operations, reduce costs, improve the overall quality of rail transport and increase competitiveness.

History

In December 1989, European Transport minister decided to formulate a strategy to develop a single Train Control System standard to apply across Europe.  A group of railway experts started to develop the requirements specification of European Train Control System (ETCS) as the base for industrial development.  The project framework included new on-board equipment, a new discontinuous and a new continuous data transmission system.  At the end of 1993, the EU council issued an Interoperability Directive and a decision was made to create a structure to define the Technical Specification for Interoperability.

In 1996, the EU decided that European Rail Traffic Management System (ERTMS) would become the standard for all high-speed lines. The EU Council Directives 96/48/EC and 1001/16/EC with respect to the interoperability of the trans-European high-speed rail system and conventional rail system were developed.  ETCS is developed as part of the ERTMS initiative. 

What is ERTMS?

ERTMS comprises trackside and trainborne systems and utilises an in-cab signalling and ATP element called ETCS (European Train Control System).  ETCS is the train control system and GSM-R (Global System for Mobile Communications – Railways) is the new radio system for voice and data communication. 

The two subsystems together form ERTMS, the new signalling and traffic management system which enabling interoperability throughout the European railway network.

ETCS
ETCS is a signalling, control and train protection system developed and promoted by European Commission.  The system aims to standardise the signalling and train control systems and remove the hindrance to the development of international rail traffic.  It specifies for compliance with the High Speed and Conventional Interoperability Directives. 

ETCS is in fact an ATP system, based on cab signalling and intermittent and/or continuous track to train data transmission.  It provides an inherently safe operational environment for the movement of trains throughout the network, while facilitating a greater network carrying capacity.  It does this through the real-time monitoring, capture and analysis of data relating to movement authorities, precise train location, train speed, braking curves and system integrity.  Based upon the analysis of this data, appropriate control orders are issued so that rail traffic operates with the shortest, most efficient, but safest headways.

GMS-R
GSM-R is a radio system that provides voice and data communication between the track and the train.  It is based on standard GSM using frequencies specifically reserved for rail application with certain specific and advanced functions.

Levels of ETCS

ETCS is divided up into different equipment and functional levels.  The definition of the level depends on how the route is equipped and the way in which information is transmitted to the train.  The scope and interface of ETCS at trackside level vary considerably for the three application levels.

ETCS – Level 1
ETCS Level 1 is a cab signalling system that can be overlay or used in conjunction with existing signalling systems.  Lineside signals are generally retained and block control is achieved in the conventional manner by the interlocking, based on the information detected by track circuits or axle counters.

It is a system based on intermittent track-to-train communication.  Balises, which are linked to the signals or interlockings via the Lineside Electronic Unit (LEU), transmit route data as movement authority to the trains.  The on-board computer continually monitors and calculates the maximum permitted speed and the braking curve. 

Figure 1 ETCS Level 1 Balise without infill
(Figure captured from: http://www.ertms.com)

Figure 2 ETCS Level 1 Balise with infill
(Figure captured from: http://www.ertms.com)

Figure 3 ETCS Level 2 Balise with GSM-R and Radio Block Center
(Figure captured from: http://www.ertms.com)

Figure 4 ETCS Level 3 Balise with GSM-R and Radio Block Center
(Figure captured from: http://www.ertms.com)

Table 1 Summary of different ETCS level

• less trackside equipment and major equipment reduction the leads to fewer breakdowns/disruptions
• increase capacity, provide quicker and more flexible train movements
• improved punctuality
• higher operational throughput and lower operations and maintenance cost
• possible to have line speeds of up to 500 km/h
• open market for signalling systems and increased competition by admitting more suppliers

Table 2 Implementation Status in Europe
(Source: http://www.uic.asso.fr)