Moving block
Encyclopedia
In railway signaling, a moving block is a signaling block system where the blocks are in real time defined by computers as safe zones around each train
. This requires both the need to know the exact location and speed of all trains at any given time, and continual communication between the central signaling system and the train's cab signaling system. Moving block allows trains to run closer together, while maintaining required safety margins, and thus increasing the line's overall capacity. Information about the location can be gathered through active and passive markers along the tracks, and train-borne tachometers and speedometers. Satellite-based systems cannot be used because they will not work in tunnels.
, London's Docklands Light Railway
, New York's line, and planned for future use on London's Jubilee Line
. It was supposed to be the enabling technology on the modernisation of Britain's West Coast Main Line
which would allow trains to run at a higher maximum speed (140 mph), but the technology was deemed not mature enough, considering the large number of junctions on the line, and the plan was dropped. It forms part of the European Rail Traffic Management System
's level-3 specification for future installation in the European Train Control System
, which will at level 3 feature moving blocks that allow trains to follow each other at exact braking distances.
But nowadays, with the current radio-based CBTC systems using the moving block principle, to reduce headway
s and increase transport capacity is very much a reality.
Train
A train is a connected series of vehicles for rail transport that move along a track to transport cargo or passengers from one place to another place. The track usually consists of two rails, but might also be a monorail or maglev guideway.Propulsion for the train is provided by a separate...
. This requires both the need to know the exact location and speed of all trains at any given time, and continual communication between the central signaling system and the train's cab signaling system. Moving block allows trains to run closer together, while maintaining required safety margins, and thus increasing the line's overall capacity. Information about the location can be gathered through active and passive markers along the tracks, and train-borne tachometers and speedometers. Satellite-based systems cannot be used because they will not work in tunnels.
Implementation
Moving block is in use on Vancouver's SkytrainSkyTrain (Vancouver)
SkyTrain is a light rapid transit system in Metro Vancouver, British Columbia, Canada. SkyTrain has of track and uses fully automated trains on grade-separated tracks, running mostly on elevated guideways, which helps SkyTrain to hold consistently high on-time reliability...
, London's Docklands Light Railway
Docklands Light Railway
The Docklands Light Railway is an automated light metro or light rail system opened on 31 August 1987 to serve the redeveloped Docklands area of London...
, New York's line, and planned for future use on London's Jubilee Line
Jubilee Line
The Jubilee line is a line on the London Underground , in the United Kingdom. It was built in two major sections—initially to Charing Cross, in central London, and later extended, in 1999, to Stratford, in east London. The later stations are larger and have special safety features, both aspects...
. It was supposed to be the enabling technology on the modernisation of Britain's West Coast Main Line
West Coast Main Line
The West Coast Main Line is the busiest mixed-traffic railway route in Britain, being the country's most important rail backbone in terms of population served. Fast, long-distance inter-city passenger services are provided between London, the West Midlands, the North West, North Wales and the...
which would allow trains to run at a higher maximum speed (140 mph), but the technology was deemed not mature enough, considering the large number of junctions on the line, and the plan was dropped. It forms part of the European Rail Traffic Management System
European Rail Traffic Management System
The European Rail Traffic Management System is an initiative backed by the European Union to enhance cross-border interoperability and signalling procurement by creating a single Europe-wide standard for train control and command systems....
's level-3 specification for future installation in the European Train Control System
European Train Control System
The European Train Control System is a signalling, control andtrain protection system designed to replace the many incompatible safety systems currently used by European railways, especially on high-speed lines.- History :...
, which will at level 3 feature moving blocks that allow trains to follow each other at exact braking distances.
But nowadays, with the current radio-based CBTC systems using the moving block principle, to reduce headway
Headway
Headway is a measurement of the distance/time between vehicles in a transit system. The precise definition varies depending on the application, but it is most commonly measured as the distance from the tip of one vehicle to the tip of the next one behind it, expressed as the time it will take for...
s and increase transport capacity is very much a reality.