German Unity Transport Project 8

 Nuremberg – Erfurt – Halle/Leipzig – Berlin

Control and command technology

An efficient command and control system will ensure a high frequency of trains operating safely along the VDE 8 route. The smooth interoperation of tried and tested track circuit technology and ESTW path identification using the innovative ECTS European train control system will play a crucial role.

Electronic signalling centres (ESTW)

AS early as the mid-1980s a start was made on converting electromechanical and relay signal boxes to electronic operation. Electronic signalling is immeasurably more efficient than the old types of signal box. Following thirty years of development and optimisation of electronic signalling systems, it can assume demanding roles - not only as part of the VDE 8 project - and above all guarantee safe railway operation.

In general, the purpose of signalling centres is to operate safety-critical external installations on the line, such as points (see illustrations below) or signals. As electronic signalling makes it possible to control large signalling areas from rail operating centres (ROCs, see illustration above), additional remote signalling computers (ESTW-A) and sub-masters (ESTW-UZ) are used. The sub-master contains the train path logic and processes data which it receives from the track circuit system and commands from the operations centre. The signalling computers are used to increase headway and connect external installations with the sub-masters.

Both new sub-masters and signalling computers are being installed, and existing sub-masters modified, in the project phase between Halle/Leipzig, Erfurt and Hallstadt. The sub-masters, which are usually unmanned, are being controlled from the Leipzig and Munich ROCs along the entire section of the route between Leipzig/Halle and Hallstadt. Use of the latest technology is creating the conditions for safe, reliable and highly-efficient rail operations.

ETCS - European Train Control System

Lineside signals, as shown in the illustration below, will only be present on the new line between Halle/Leipzig, Erfurt and Hallstadt around junctions with lines on which ETCS does not operate. The entire line will be equipped with ERTMS/ETCS, Level 2, which renders lineside signals superfluous.

Unlike ETCS Level 3, which has not yet been approved for use in Germany and in which trains can move in variable "moving blocks" - the length of the individual consecutive sections is no longer rigidly dictated by the locations of block signals - fixed block sections are used for ETCS Level 2. The number of block sections depends upon the length of the route and the desired train frequency.

An efficient, reliable track circuit system, multiple-block axle counters and ETCS prevent a following train from entering an occupied block section.

Block sections are delimited by block indicators. Colour light signals no longer meet the requirements of a line with a maximum speed of 300 km/h, because a train driver cannot see or recognise lineside signals in time at this speed. The train is equipped with cab signalling, which displays the highest permissible speed to the driver. This requirement is implemented by ERTMS/ETCS Level 2 in this case. The advantage over other train control systems, e.g. continuous automatic train running control, lies in the smooth cross-border traffic made possible by technical harmonisation. Hitherto, time-consuming changes of locomotive or expensive multiple-system locomotives have been necessary for this purpose.

ETCS is a stand-alone train protection system which is facilitating cross-border rail traffic in Europe. An important task is the issue of movement orders; "You can proceed to milepost xyz at 300 km/h". In ETCS Level 2, such movement orders are transmitted over GSM-R and monitored by the on-board terminal. Tried and tested eurobalises (see illustration below) fulfil a whole range of tasks. They support automatic train location, order level changes in the national train protection system, etc.

Electronic signalling centres continue to control track circuits, the setting of points and signals, etc.

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