SCMT is an acronym for Sistema Controllo Marcia Treno (Train Gear Control System) and refers to a set of equipment, features and technologies that support the rolling stock conduct on an "old" or not adequately equipped line (i.e. that not complying with the ERTMS standards (European Railway Traffic Management System). These tests allow to increase the safety level and, as well, let the means travel at higher speeds.

The data transmission occurs only between the ground equipment (or Ground Subsystem - SST) and the board (On-board Subsystem - SSB), responsible for controlling the train speed at a particular point of the line. The driver is not able to see anything of what is passed between the SST and the SSB; he must, therefore, guide the train in accordance with the instructions received from the signal line and from the movement prescriptions.

The system can be complemented with other certain features:

• SSC (Conduct Support System): in many ways similar to the SCMT, it is able to support the SCMT and, in some cases, even to replace it in order to assist the train crew;
• RSC (Continuous Signals Repetition): the on-board subsystem that picks up some codes (AC, 75, 120, 120 *, 120 **, 180, 180 *, 180 **, 270, 270 * and 270 **) arriving from an appropriate equipment placed on the rails and, thus, adjusts its own behavior.

Inside the lab, testing tasks can be performed thanks to the help of suitable test benches (simulators) that include devices, commonly present in the train’s cabin, and some items necessary to simulate signals arriving from the ground or from bulky equipment. Some of the equipment typically found on board is as follows:

• MMI (Man Machine Interface): a device to display the indications that the system turns to the driver. Using the appropriate buttons, the crew forwards commands and change the behavior of the rolling stock. Generally, there are two MMIs present in each train, one per cabin when there are two cabins, or one running and one standby when the train is a mono-cab;
• Cubicle: the "brain" of the on-board system. It receives signals from the train’s units; if necessary, processes them and transmits them to the dedicated elements. The cubicle is, in fact, like a cube-shaped metal cabinet and consists of multiple circuit boards, each of which has its own specific purpose. The main board is called SMART, it houses the most important decision-making bodies. The Smart is made of three structurally identical sections; at the decision making, it gathers votes and, once the majority is reached, communicates the result to the rest of the system;
• Speedometer: an analogous speed indicator, equipped with some lamps to indicate when the train is ready to move and when it is in the braking phase;
• Radio equipment: devices necessary for establishing a radio connection between the board and the ground.

The simulation elements that complement the work mainly of equipment on board are:

• Master Simulator: a computer that interfaces the test benches through the appropriate interface boards and which, with the help of the SimuMaster software, can command the benches. The Master Simulator is also able to emulate some types of signals that, in real conditions, the on-board system board would receive from the ground;
• MVB Simulator: a computer responsible for the MVB administration and management, the channel on which various simulator elements exchange information;
• Bacc Simulator: a device providing RSC codes to the system, i.e. those signals that in real-life situations come from the ground side. The simulator sends the codes to sensors, which in the case of laboratory machines are simulated through certain technical devices.

Once the simulator is complete and fully-functioning, it is possible to proceed with the testing phase; this can be substantially divided in two main branches: strength tests and functional tests.

Strength Tests

The strength tests are mainly physical tests, designed to monitor the system behavior against any sudden failure. The reaction of the train to abnormal situations must conform to Alstom internal specifications; if it does not happen, the problem must be appropriately registered in order to facilitate a future resolution.

The tests involve simulator apparatus that comes from the real board and are made both at physical level (by removing or temporarily disconnecting some elements), and at software level (i.e. by acting on the internal system parameters or simulating ad hoc operations). The results are registered (along with necessary attachments) into appropriate documents and internal reports.

Functional Tests

The functional testing is necessary to verify the proper implementation of the system functional requirements. The test strategy is "Black Box", that is, independent of the internal behavior of the system and of its structure and aimed to ensure that expected requirements are met. For this reason, during these tests, the system responses (output) to various stresses (input) are observed; all is done in accordance to the system specification. The verification of the functional requirements of the SCMT On-board Subsystem is performed on the testing platform that allows to conduct automated testing (i.e. tests automatically run and test cases automatically checked).

Such a platform, called "Intellilog", was created to automate the result verification for each test case. It delimits, as far as possible, manual operations which, by their nature, are more prone to errors. Thanks to this automatic testing platform, it became possible to automatically execute text cases both in the host environment - protected and restricted to only an application part of the on-board subsystem – and in the real target environment, thus reducing the operator’s intervention at the start up step and during the test session closure.

To sum up the Functional testing phases, there can be emphasized:

STEP 1

Defining a language for the test procedure formalization. The language includes information on both tests to be performed and on actions requested to PdM (Personal machine) for the testing.

STEP 2

“Intellilog” interprets the language defined during step 1 and runs all the tests on a diagnostic log file (received from the on-board subsystem); then, it produces a detailed report and a synthetic result (PASS or FAIL)..

In summary, the activities of SCMT functional testing can be defined by the following points:

• Optimization and Automation of the SCMT / SSC testing in the ERTMS / SCMT frameworks: collaboration in the development of tools for test execution and automatic verification, formalization of SCMT / SSC functional test specifications into the form of an XML script.
• Writing of Test scripts and Test scenarios.
• Writing of Test Specifications and Test Reports.
• Coverage and traceability of the SCMT SSB / SSC system requirements through an ad hoc test cases definition.
• Analysis and management of fails/anomalies of the SCMT SSB/SSC.

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