DIN EN 50122-2/A1-2003 轨道交通.固定设备.第2部分:直流牵引系统杂散电流防护措施.修改件A1
Railway applications - Fixed installation - Part 2: Protective provisions against the effects of stray currents caused by d.c. traction systems; Amendment 1; German version EN 50122-2:1998/A1:2002