The growth of technology accompanying the economic growth of recent decades has itself been accompanied by increased exposure of the population to electromagnetic fields.
An electromagnetic field is determined by its frequency and wavelength: the first describes the number of oscillations per second, while the latter is the distance between waves.

The WHO (World Health Organisation) provides the reference for the assessment of risks related to human exposure to electromagnetic fields.

Since the early 1980s, in collaboration with qualified national structures such as the Istituto Superiore di Sanità (Italian institute of health), ANPA (environmental protection agency) and Enel, the main Ferrovie dello Stato Italiane operating companies have provided a genuine contribution to analysing and assessing the interaction between the environment and the electromagnetic fields created on the rails.

Many investigations have been conducted to check that the electromagnetic field thresholds pursuant to law are complied with, both on board operating trains and in the areas surrounding the infrastructure that generates the radiation.

In particular, the following railway systems generate electromagnetic fields with non-negligible frequencies under current legislation:

• electrical power lines and stations, i.e., all electrical lines, substations and transformation stations;
• electrical traction contact cables;
• telecommunication and radio transmission systems used to meet service requirements;
• medium and low voltage systems for lighting and other services.