2011DIN EN 50122-2:2011 Railway applications - Fixed installations - Electrical safety, earthing and the return circuit - Part 2: Provisions against the effects of stray currents caused by d.c. traction systems; German version EN 50122-2:2010
1999DIN EN 50122-2:1999 Railway applications - Fixed installations - Part 2: Protective provisions against the effects of stray currents caused by d.c. traction systems; German version EN 50122-2:1998