Automatic optimal balise layout

The number of balises: an important parameter in the cost of commissioning CBTC systems

By transmitting data from track to trains, balises are critical to locating and spacing trains. the balises make it possible to define the location of the train and thus manage the spacing. They are an essential signalling element for safety and traffic optimisation. Whether for operators or suppliers of train control systems, upstream studies, installation and maintenance of balises have a significant cost impact on the deployment of each line.

Automation of costly and non-optimised traditional processes

Systerel has designed an automated and parameterised solution for calculating the location of balises, making it possible to minimise their number while respecting the system’s performance requirements.

BLAST is looking for a solution using the minimum number of balises to handle all the requirements associated with the line in question, while providing for each balise the list of requirements that led to its positioning. It takes into account installation prohibited areas and optimises the effort associated with iterations resulting from changes in context.

In this way, the comparison of different sets of rules and the measurement of the economic impact of a modification on a requirement can be carried out very quickly.


BLAST allows not only to minimise the number of balises, but also to adjust the rules as the field surveys and to calculate the number and position of the balises very quickly: 15 minutes  with the assurance of a quality and optimised result as opposed to several days manually.

In this way, we obtain:

  • An optimal result: the number of balises to be placed is minimal, which cannot be guaranteed with a manual approach.
  • A simplification of the industrial process: the specification is simplified: the engineer focuses on the expression of his needs, the mutualisation of constraints is made by the solution.
  • A design in DTC mode (Design at Target Cost): achievable savings for alternative rules can be quickly quantified, especially when rules depend on external systems performances (e.g. rolling stock).

Its solution has been successfully tested 

  • L6 of Paris metro with Alstom: Definition of the layout of the balises and study of various odo tachymetry alternatives
  • L11 of Paris metro with Alstom: Definition of the layout of the balises and study of several approach rules for out-of-station stops.
  • L3 of Paris metro: ~30% fewer balises than the reference solution studied on existing projects.

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