DS EN 50152-3-1:2003 Railway Applications - Fixed Installations - Particular Requirements For A.C. Switchgear - Part 3-1: Measurement, Control And Protection Devices For Specific Use In A.C. Traction Systems - Application Guide Gives assistance, guidance and requirements in the design of protection, control and measuring systems in a.c. installations at traction voltages intended to provide a power supply to traction systems