A joint committee from the Engineering and Mechanical Divisions of the Association of American Railroads has been .sponsoring research work for some years aimed at finding a means of preventing damage from refrigerator car brine drippings to the track, bridges and car itself. Initial studies indicated addition of sodium dichromate neutralized with soda ash to the salt and ice in the bunkers of the cars would effectively prevent corrosion from brine drippings. However, because of the toxicity of the dichromate it was found necessary to add the inhibitor externally of the car by passing the brine drippings through a suitable filter in order to avoid contamination of the lading. Further work indicated development of such a filter was possible but the cost of servicing filters on each refrigerator car made the use of dichromate appear questionable economically.
Studies with other inhibitors more recently developed have indicated Sodium Polyphos will be equally effective from the standpoint of preventing corrosion, and since it does not have the undersirable toxicity, it can be added directly with the salt. The cost of Sodium Polyphos as an inhibitor is not much greater than dichromate for equal protection, so it appears it will offer much more, economical means of controlling corrosion. Additional work is necessary to determine the most effective inhibitor concentration and most economical method of application.
