Automatic Train Control System - SCMT

The most common ATP system in operation on the Italian National Railway Network called SCMT.

More than 11,000 km of mainline have been recently equipped with this discontinuos train Cab signalling system whose main purpose is to control the respect of the speed limit imposed by the signal aspect and the line condition.

The system is fully compliant with the European ERTMS/ETCS Level 1 and is designed to provide enhanced levels of rail safety through continuous train control and protection. The SCMT solution has the following functions:

  • Train control in accordance with signal settings;
  • Train control in accordance with maximum permitted line speeds and line gradients (in normal and degraded operating conditions);
  • Train control in accordance with the maximum permitted speeds for rolling stock;
  • Train control in accordance with slowing and speed reduction rules.

The system comprises a wayside subsystem (SST) and an onboard subsystem (SSB), which are closely integrated.

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

The wayside subsytem is based upon an array of transponders (Eurobalises) called "Punto informativo - PI" and Lineside Lineside Equipment Units (LEUs). PIs are placed on the tracks - near signals, reduced speed zones or other important points along the line - while LEUs (Lineside Equipment Units) are connected to the Eurobalises® and change the message sent to the train according to IXL conditions and signal aspects.

When a train passes over a PI, a set of "antennas" mounted in front of the first boogie (Balise Transmission Module - BTM) energize it through induction. The PI then passes information about the aspect of the next signal to the onboard subsystem that elaborates a "braking curve" indicating the speed the train has to respect during the approach to the signal, until the "target speed" is reached.

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
  • When energized by RSDD Antenna, sends a telegram to trains in transit
  • FIXED Balise: Stores infrastructure data as pre-formatted telegrams, specifying instance position reference, speed limits, line gradient, works on the line etc
  • SWITCHABLE Balise: Sends telegrams to train from LEU that contain movement permissions and trackside data

Read more about Eurobalise


Onboard Subsystem

The onboard subsystem receives and analyzes the information about the track status and characteristics of the movement permission sent by the Eurobalise. It automatically applies brakes if the comparison of the actual speed with the permitted speed shows that restriction of the speed must be observed.

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
Man Machine Interface (MMI)
  • LCD touch screen panel to interact with the driver for control and indication functions

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