A train path is the infrastructure capacity needed to run a train between two places over a given time-period.
[Definition fro]
Directive 2001/14/EC
Article 2 (l), of the European Parliament and of the Council Within the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
, a train operator needs to purchase a train path from a rail infrastructure company to run a
train
In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and Passenger train, transport people or Rail freight transport, freight. Trains are typically pul ...
on their tracks.
Overview
The number of rail paths available on a given railway line depends on a number of factors. The number of tracks and the type of
signalling
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
, specifically the number of blocks, are limits set by the actual infrastructure. A variable factor is the speed difference between trains. Optimal capacity is achieved when all trains run at the same speed. When that is not the case, faster trains will eventually catch up to slower trains, so trains have to be spaced much further apart to avoid interference.
Applications
Usually, train operators apply for train paths over a given period several months before the start of the period. After a deadline has passed, the rail infrastructure company uses all applications to create the working timetable. A number of rail infrastructure companies have defined different classes of train paths. More expensive classes are treated with priority during timetable construction and operation.
Delayed trains
If a train is delayed beyond a certain tolerance, it will "fall out" of its allocated train path. On congested lines, this will result in additional delays, as such a train is taken to
passing sidings whenever that is necessary to let other trains pass.
Graphs
Train paths are usually shown on a time-distance graph, where time is shown horizontally, and distance (including a representation of the track layout) is shown vertically.
References
Rail infrastructure
Rail transport operations
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