Tramway ”D line” of Bordeaux: Innovative solutions for availability management
One of the main challenges of D Line is both the availability and reliability of the signals that allow rolling stock to move without incident.
In general, in dual track, the operation of a tram system is that of Line of sight. This means that it is the driver who performs the "signalling" function. The driver controls and regulates the speed of the tram in order to ensure there is the necessary spacing in relation to the previous tram.
In specific cases such as switches and for bi-directional parts of the line or single-track sections, arrangements must be made to avoid any risk of any trams meeting head on. In these cases, using Line of sight does not meet the safety requirements and thus technology supports the operation to manage the signalling function.
The combination of on-track sensors along with their evaluation units installed inside cabinets makes the Frauscher Advanced Counter FAdC system a safe package that meets the SIL 4 standards required in the Bordeaux Line D market. In support of the availability of operations, this system incorporates innovative management methods, including Counting Head Control CHC.
In order to compensate for the counting errors, which are common in urban areas as they are often caused by stray metal objects (cigarette papers, soda cans, etc.), some track sensors can be set to "sleep" under certain conditions. Thus, the system is not disturbed due to untimely occupations. Counting heads only "wake up" when a train occupies the adjacent track section. This innovative concept patented by Frauscher has been implemented without additional hardware as part of the D-line market.
Simple and fully customizable, as part of line D, the Counting Head Control algorithm waits for three successive disturbances which are not related to rolling stock to "wake up" the counting head and indicate an occupation.
For all French tram networks equipped with a Frauscher axle counting system, the Bordeaux tramway is the first French tram system to benefit from this innovative concept.
