The present IRS sets out guidelines to ensure optimum safety for staff working on or near overhead railway contact lines supplied in DC or AC current with the following voltages: 1,5 kV and 3 kV DC; 15 kV - 16 2/3 Hz; 25 kV and 2 x 25 kV - 50 Hz. The requirements provided in the present IRS aim to ensure safety during maintenance and other works. They apply to all electrical and non-electrical work activities. The present document focuses on electrical hazards; the risks arising from train traffic and other causes are only summarised.