MECHANICAL TESTS FOR RAILWAY APPLICATIONS

With a long experience in the railway sector, Istituto Giordano offers test services designed to meet its technical and regulatory requirements.

Complete with state-of-the-art equipment subjected to continual testing and calibration, the laboratories guarantee maximum precision and reliability of the tests performed. Amongst the tests conducted, mechanical ones for the railway sector are carried out in the vibration laboratory and regard:
 

• railway infrastructures, mainly safety and signal equipment, regulated by RFI technical specification “DI TCSS ST IS 00 402 A” or IS 402 for short;
• rolling stock equipment tested in accordance with the requirements of standard EN 61373.

A category is assigned to these products based on the installation environment that will then determine test severity. Furthermore, the nature of tests performed is common to both railway infrastructures and equipment:
 

• shock tests: these are isolated, sporadic events that can occur during the product's lifetime;
• duration or “fatigue” tests: these are generally random vibrations, “concentrating” into just a few hours the cumulative stress to which an item is subjected throughout its lifetime under working conditions.

 
Mechanical strength and retention of performance/operating efficiency upon test completion indicate whether a product is fit to be awarded the requested test class.
 

IS 402 mechanical tests.

The RFI IS 402 specification is split into three macro-areas that include tests regarding “environmental” (Part III), “electrical” (Part IV) and “electromagnetic” (Part V) conditions.
In the section covering environmental conditions, also including vibration and shock testing, five factors are specified:
 

1. mechanical
2. climatic
3. biological
4. chemically active substances
5. mechanically active substances

From 2 to 5 installation environments are specified for each factor and these are used as a basis for assigning the equipment groups. These last-named define the test conditions to be applied in accordance with the methods/standards of the IEC 60068-2 series. Mechanical tests specify 5 installation environments:
 

• Group 1V: environments not subject to vibration (station buildings);
• Group 2V: environments protected from significant vibration, with products installed at a distance exceeding 1 metre from the track;
• Group 3V: environments subject to low levels of vibration and shock, with products installed at a distance of less than 1 metre from the track, but not mounted on the track or its support;
• Group 4V: environments subject to high levels of vibration and shock with products mounted on the track support (sleeper or concrete platform);
• Group 5V: environments subject to very high levels of vibration and shock with products installed on the track.

As evident from the descriptions, as the group category increases from 2 to 5 (group 1V equipment does not need to be tested), the test conditions become progressively more severe.
Products are tested along each of the 3 axes, identified (with reference to equipment orientation with respect to track direction) as: longitudinal, transverse and vertical. For each axis, the sequence of tests performed is as follows:

1. initial response investigation of critical frequencies (sinusoidal vibrations)
2. fatigue test (sinusoidal vibrations for groups 2V and 3V, random vibrations for groups 4V and 5V)
3. functional performance tests with random vibrations
4. final response investigation of critical frequencies (sinusoidal vibrations)
5. shock resistance

Watch the video made in our vibration laboratory of a product belonging to mechanical group 3V. More specifically, the test item is a device called “Joint Unit” which, together with the “Wheel Double Detector” device, constitutes the “Integrated Electronic Pedal System” designed to safely detect the axles of a passing train.





Tests are conducted in accordance with the methods specified in the following standards:

• IEC 60068-2-6 (sinusoidal vibrations)
• IEC 60068-2-27 (random vibrations)
• IEC 60068-2-64 (shock)

The Istituto Giordano vibration laboratory is Accredia-accredited to perform these tests in accordance with standard UNI CEI EN ISO/IEC 17025:2018.

 

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