Galvanic Anode Designs for Steel Casings on Water, Sewer and Railroad Crossings, Texas (2025-2026)

A steel casing is a larger pipe around a carrier where it passes under a railroad or a road, or where it needs room to be replaced. The casing sits in soil like any other steel, and if it corrodes through or touches the carrier, the carrier can lose its own protection. In 2025 and 2026 we prepared three small designs that put galvanic anodes on casings and give testers a way to check them.

A railroad crossing

In April 2025 a corrosion contractor asked for a design for a 54-inch casing where a line passes under a railroad. Two cased-crossing anode test stations, one beside a manhole, each carry nine 60-pound magnesium anodes. The drawings show the station plan and profile, the terminal board, the anode configuration and alloy, the buried tap connection and a concrete valve box.

A city water line

In October 2025 a design for the casings on an off-site water line in the Fort Worth area followed the city standard details: magnesium anode installation, anode test stations, permanent reference electrodes, and brazed thermite connections. Using the city details means the city crews who test the line later find what they expect.

New casings around old pipe

The March 2026 design was the reverse case. New steel casings were going around pipe that was already in service: 120 feet of 66-inch casing around an existing 48-inch ductile iron water line, and 110 feet of 20-inch casing around an existing 8-inch sewer line. Each of the four cased-crossing anode test stations carries 60-pound magnesium anodes, three per station on the large casing and two on the small one.

Related services

Designs like these are described under cathodic protection design. Checking a casing once it is built is part of start-up and commissioning.