SCMT/SSC Onboard Sub-system BL3

Designed to allow complete interoperability between the two ATP solutions (SSC and SCMT) in operation on the Italian natational and regional railways.

The system was deemed to integrate into a single on-board platform the functionality of SSC which has been deployment over the secondary lines, and SCMT (Sistema di Controllo Marcia Treni), the ATP system deployed over the main Italian lines.

The objective of the new BL3 Platform is to allow interoperability among the two systems, so that trains could pass from a secondary line equipped with SSC to a main line equipped with SCMT without having to manually switch the protection system or, worse, to change locomotive.

The system manages these transition areas, making the actual mode switching transparent and, at the same time, ensuring continuous train protection. In other words, this means the installation of only one onboard subsystem instead of two, drastically reducing the necessary footprint and CAPEX while assuring no compromise to safety.

Served Railways
Mass TransitMass Transit
Main & RegionalMain & Regional
Heavy HaulHeavy Haul
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Wayside Subsystem

The trackside subsystem provides the transmission of information about signal aspects and other fixed data (line speed, braking curves, distance to next signal, speed restrictions) to the on-board subsystem via microwave link (SSC) and eurobalise (SCMT).

Interlocking LEU
  • Captures movement authority information from interlocking system
  • Selects and sends telegrams to Eurobalise that contain movement authorities and track status data
Interlocking LEU
Signal LEU
  • Acquires signal status by directly interfacing light signal and measures electric current transferred from interlocking system to signal
  • Sends telegram to Eurobalise
Signal LEU
  • Modulates the telegram and transmits it to the on-board equipment over a microwave communication

Onboard Subsystem

The onboard subsystem protects trains in sections fitted with both SCMT (with or without BAcc) and SSC wayside equipment. The two logic units and Air-Gap interface devices (RSC, SSC and SCMT) are continuously active, each working in its own operational mode. Each of the two logic units, communicating with the each other, determines the operational mode allowed. The SCMT system acts as master when taking these decisions.

RSDD Train Antenna
  • Energizes the Eurobalise
  • Receives the telegram sent by the trackside balises
RSDD Train Antenna
Balise Transmission Module (BTM)
  • Manages the Eurobalise interface
  • Controls the supply of energy for telepowering the balises
  • Receives and decodes the telegrams coming from the balises
European Vital Computer (EVC)
  • Applies the Automatic Train Protection logic
  • Acts as the Interface with the train's main functions (odometry,etc...)
  • Manages the vital functions of the on-board subsystem and provides support for diagnostic maintenance of the on-board subsystem
BACC Sensors
  • Receiver sensors in front of the first axle of the train to detect the coded current in the rail
BACC Sensors
SSC Antenna
  • Receives telegrams over a microwave communication with wayside subsystem
Man Machine Interface (MMI)
  • LCD touch screen panel to interact with the driver for control and indication functions

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