Railway cathodic protection

If the buried storage tank is built near the railway line, the soil is polluted by garbage and has strong corrosivity, so cathodic protection is particularly important. Due to the particularity of railway operation, in addition to the general requirements, it should also comply with the company's special technical standards. All rail joints must be connected to a good conductive cross connection on the track to which the hazardous area leads. There must be a low resistance connection between these rails and the loading nozzles of the tank unit.


If the protection current of the cathodic protection cell unit is too high due to this connection, an insulated joint should normally be installed on the line where the nozzle is installed. Extreme care must be taken not to disconnect continuous low resistance connections. If the rail is permanently connected to the filling equipment, but there is a risk of stray current from the DC rail, a continuous low resistance connection can only be achieved during the filling operation.


On extended power lines, oil filled tracks without overhead conductors are usually separated from the rest of the railway network by insulated joints in order to minimize the current flow from the railway to the tank installation. The insulated joint shall be installed outside the dangerous area, especially at the starting point of the terminal power line and both sides of the dangerous area. On both sides of the dangerous area, the power line shall be connected with other lines on both sides. If the protective current of the tank unit does not increase significantly after the refueling device is connected to these power lines, there is no need to install insulation on the pipe connecting the tubing nozzle.


Insulated joints shall not be installed on oil rails with overhead conductors. During loading, overhead conductors must be closed and can be connected to track ground. In these cases, insulated joints must be installed in the pipe connecting the nozzle for cathodic protection of the tank installation.