19_ERTMS ETCS Level 2

ERTMS / ETCS Level 2 ________________________________________ ERTMS / ETCS Level 2 – High-Speed Rail Signaling and Control Systems Today we are going to study ERTMS / ETCS Level 2, which is one of the most important and widely implemented levels of the European Train Control System. Level 2 represents a major technological shift from conventional signaling to modern radio-based train control. Understanding this level is essential for anyone working in advanced railway signaling and high-speed rail operations. Introduction to ETCS Level 2 ETCS Level 2 is the second operating level of the ERTMS/ETCS system. Unlike Level 1, which relies mainly on intermittent communication through balises, Level 2 is based on continuous transmission of information from track to train. This means that the on-board equipment always has real-time and up-to-date information about the condition of the track ahead. As a result, Level 2 provides: • Higher safety • Better operational efficiency • Higher permissible speeds • More reliable train control Continuous Radio Communication The key feature of Level 2 is continuous radio communication. At this level, all important information required for train operation is sent continuously from the trackside to the train through a central control unit called the RBC – Radio Block Centre. The RBC is connected with the interlocking system, which safely sets and locks train routes. So the overall concept is: • Interlocking decides the route • RBC receives this information • RBC communicates it to the train in real time This creates a fully supervised and centralized control system. Role of GSM-R Communication between the train and RBC is made possible through the GSM-R network, which is a railway-dedicated mobile communication system. An important point here is that communication is bidirectional. This means: • The train receives information from RBC • The train also sends information back to RBC Because of this continuous radio link, controlled balises are no longer required in Level 2. Only fixed balises are used, which we will discuss next. ________________________________________ Function of Fixed Balises Even in Level 2, balises are not completely eliminated. However, their role becomes very limited. Fixed balises are used only for two main purposes: 1. To determine the exact position of the train 2. To provide static speed profile information Precise location of the train is calculated using: • Balises • On-board odometry equipment So, balises act as reference points rather than as primary signal transmitters. Movement Authority (MA) One of the most important concepts in Level 2 is the Movement Authority, commonly called MA. The RBC sends the Movement Authority to the train. This MA contains: • Geographical data of the route • Distance to the next obstacle • Status of track circuits or blocks • Limits up to which the train is allowed to move safely The obstacle may be: • Another train ahead • An occupied block • A stop point • Any restriction on the track Based on this MA, the train knows exactly how far and how fast it can proceed. Cab Signaling Concept A major change introduced in Level 2 is that traditional lineside signals are no longer required. All driving information is directly shown inside the cab on a screen called the: DMI – Driver Machine Interface The driver receives: • Permitted speed • Target distance • Braking curves • Movement Authority information So, instead of looking outside at signals, the driver follows the instructions displayed inside the locomotive. This is known as cab signaling. Train Protection Mechanism Safety supervision in Level 2 is fully automatic. If the driver does not follow the instructions shown on the DMI: • First, the system gives a warning • If there is still no response, the service brake is applied • In a critical situation, the system applies the emergency brake This ensures that: • Human error is minimized • The train never crosses the safe limit • Accidents due to signal passing at danger are prevented Thus, Level 2 provides a very high level of automatic train protection. ________________________________________ Train Position Detection Even though communication is radio-based, train detection on trackside is still required. In Level 2: • Track circuits or axle counters continue to be used • Odometry equipment on the train measures speed and distance • Balises help in correcting position errors The odometry system continuously: • Monitors train speed • Compares it with permitted speed • Calculates safe braking curves This combination ensures accurate and reliable train localization.