Sistema di Controllo della Marcia del Treno
Sistema di Controllo della Marcia del Treno (abbr. SCMT ) is a train control and command system that is used in the RFI network in Italy . It can run under ETCS Level 1 and use Eurobalises to transfer data between the vehicle and the route. It consists of the subsystems "SST" ( Italian Sottosistema di Terra = "track-side subsystem" or track equipment) and "SSB" ( Sottosistema di Bordo = "on-board subsystem" or vehicle equipment). The terms SST and SSB come from the EU regulations on interoperability.
SCMT is produced by the Mermec company.
Overview of SCMT vehicle equipment
The Italian SCMT can be used nationally as the sole control and command system. The European ETCS enables the integration of national systems, so that the SCMT as a national system can also be active under ETCS.
The SCMT vehicle equipment essentially consists of the following components:
- Antennas for detecting balises telegrams
- Antennas for recording the continuous signal feedback (RSC, Ripetizione Segnali Continua)
- An odometry device to record the distance covered
- Two master computers for train control and protection (RSC) and train control (CMT)
- Display and control unit on the driver's desk
- Intervention in the train control to initiate emergency braking.
- Braking group for controlling automatic braking
SCMT integrates two different control systems: RSC ( Ripetizione Segnali Continua , train control and safety) and CMT ( Controllo Marcia Treno , train control). Depending on the operating mode, which has to match the respective track equipment, the two systems can work individually or also work together in addition. RSC is the older system. In the meantime, all RSC lines have also been equipped with SCMT balises, so that in this case both systems work together.
The task of train control systems is to calculate and monitor permissible speeds on the route being traveled. This is usually done using sensor technology in the track and detection technology in the vehicle (“local”).
The task of train control systems is to ensure that all trains traveling on a route are sufficiently distant from one another (block sections and travel permits, which may or may not be issued for them). This control is usually carried out by the dispatcher or control center.
The task of train control systems is to combine the two as optimally as possible in order to relieve the driver as much as possible.
If a train exceeds the permitted speed z. B. at 3 km / h or 5 km / h, the system initiates emergency braking.
Thanks to the detailed information that is transmitted and the precise monitoring of the train journey, the system can check whether the train is complying with the currently permitted speed and braking curves - it should therefore be impossible to exceed the speed limit or unauthorized passing signals that indicate a stop.
RSC vehicle equipment
The " Ripetizione Segnali Continua a 9 codici " ( continuous signal feedback with 9 signal terms ), in short " RSC 9 Codici " ( RSC9 ) is an extension of the RSC previously used in Italy with four signal terms (see RS4 Codici ); several different codes can be received and differentiated from the track. When the RSC system is active (RSC button lights up blue), the corresponding code symbols are displayed on the screen of the operating and display device. The icon for the received code is highlighted in color.
Depending on the code received, the RSC system calculates the maximum permissible speed for the current block, taking into account the train data entered.
CMT vehicle equipment
The “ Controllo della Marcia del Treno ” function ( train schedule control) in the SCMT monitors the train's permissible speed. The basis for calculation is the route data received and the train data entered by the train driver. A distinction is made between two types of speed limitation:
- permissible constant speed and
- Reduction of the permitted speed.
In order to avoid jumps in the speed curves, a curve on a target point of the route to the lower speed is calculated when a speed reduction is required. Higher speed limits take effect immediately.
The permissible speed is calculated for different levels:
- for the rank of the train ("rango")
- for the rank of the route ("grado")
- for time of day limitations
- for speed restrictions
- in the case of passivated train control systems
- for passing branching points
- for approaching stop signals
The SCMT control unit does not provide the driver with any displays, apart from the activity display of the CMT system (SCMT button lights up blue).
RSC track equipment
The RSC codes are transmitted over the tracks using modulated alternating voltages. The tracks are divided into blocks (usually 1350 meters, but shorter and longer blocks are also possible) and each block sends a code. Turnout areas cannot be coded.
The following codes can be transmitted:
| code | meaning |
|---|---|
| AC | No code (behind stop signals, in the turnout area, occupied blocks) |
| 75 | Announcement of a stop signal (at the end of the block) |
| 120 | In front of a main signal that indicates driving permission with a turnout of 30 km / h or 60 km / h |
| 120 * | In front of a main signal that shows driving permission with a turnout of 100 km / h |
| 120 ** | Code is not used |
| 180 |
|
| 180 * | If the distance from the end of the block to the stop signal is less than 2700 meters and the next sub-block has the code 180 |
| 270 | Free route for at least 2700 meters (two blocks) |
| 270 * | Free route for at least 4050 meters (three blocks) |
| 270 ** | Free route for at least 5400 meters (four blocks) |
SCMT track equipment
Route data that the SCMT vehicle equipment needs to calculate the current permissible speed of the train is received from balises. The balises are mounted in the middle of the track and send a data telegram to the train when it passes over them. The train must be equipped with appropriate antennas.
The balises are arranged in groups. Usually groups of two balises are used, but groups of four are also allowed. Each group contains a unique ID in the telegram. The balises in a group are three to seven meters apart.
The tracks are equipped with balises for both directions of travel. The numbering of the balise telegrams within each group enables the direction for which the data is intended to be recognized. Telegrams with ascending numbering are to be used for the direction of travel.
Balise groups are linked to one another, i. H. the next group is announced in the last telegram received. This can be done via the distance to the next group or the type of the next group. If an announced balise group is missed, the CMT system can initiate various measures, including an emergency brake.
There are so-called fixed balises (also: fixed data balises) that always send the same telegram, and switchable balises (also: transparent balises) that can send several different telegrams, e.g. B. depending on the signal state.
In addition, there are also mobile balises that secure speed limits.
Nine different telegram types are defined for the SCMT line equipment. Each telegram consists of a header, the telegram type itself and the data part. Some data are contained in several telegram types.
The subsystem responsible for the balise communication of the SCMT is also known under the name Ripetizione Segnali Discontinua Digitale (RSDD).
distribution
The equipment with SCMT has been completed on the entire main and feeder network ( rete fondamentale e complementare ). This also applies to the retrofitting of the locomotives. An extension to the remaining branch lines ( rete secondaria ) is not planned, a much simpler and more pure train control system (SSC, Sistema Supporto Condotta) is used there.
With the exception of RS4 Codici - whose main focus is less on the control of the train journey than on the continuous driver's cab signaling - there was no train control system before the SCMT in Italy that monitored signal observance. The entire Italian route network is now fully equipped with train control systems. On July 30, 2015, 11,856 km were equipped with SCMT, 4,242 km with SSC (of which 221 km double with SSC + SCMT) and 654 km with ERTMS.
Individual evidence
- ↑ Automatic Train Control System - SCMT
- ↑ Gavino Vargiu: Sottosistema di Terra SCMT. (PDF) Rete Ferroviaria Italiana , November 10, 2008, p. 3 , archived from the original on January 7, 2017 ; Retrieved January 7, 2017 (Italian).
- ↑ APPENDIX Technical specification for interoperability (TSI) for the subsystem "Train control, train protection and signaling" of the conventional trans-European rail system. (PDF) 2006, archived from the original on October 22, 2006 ; accessed on January 7, 2017 (1.6 MB).
- ^ Driving Support System - SSC
- ↑ Detailed technical documentation on the website of the rail network operator RFI
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