Page 286 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

264 CORROSION CONTROL AND PREVENTION

any specific corrosion-related problems that cannot be found in other sectors of the
national economy, for example, corrosion of heat, ventilation and air-conditioning
systems; corrosion of reinforced concrete floors in parking garages, or corrosion
of buried metallic structures. Corrosion of buried metallic structures is primarily
manifested in USTs or buried fuel lines transporting fuel from tank farms. Larger
airports generate considerable volumes of wastewater during the deicing season and
may have wastewater treatment facilities.
Some relevant references are given below:

1. US Bureau of Transportation statistics data, 1999.
2. Chapter 7, Airports, Airline Handbook, www.air-transport.org, June 2000.
3. FAA DOT/TSC ACAIS database, 1999.

4.17 RAILROADS

Published information with respect to corrosion-related issues is scarce.
Corrosion-prone items are rail and steel plates for wooden ties. Barlo et al.
identified the corrosion of electrified trains that covered a number of transit systems.
Stray current that occurs on the electrified rails system was found to cause corrosion.
Accelerated corrosion of the insulators of the rail fasteners and wood tie spikes
has been observed, and the wood tie spikes had to be replaced after 6 months instead
of 25 years. Corrosion damage to other railroad-owned property such as bridges, rail
yard structures occurs.

4.17.1 Corrosion of Railroad Cars
The largest costs to the railroad cars are because of corrosion of the exterior and
interior of the railroad cars. External corrosion of the cars is primarily because of
atmospheric exposure. Although corrosion damage is of concern, it is the appear-
ance that takes precedence. Therefore, the car manufacturers or lessees often choose
to apply an exterior paint coating. The paint systems used are direct-to-metal (DTM)
epoxy or epoxy with a urethane coat. The epoxy coating also protects the railroad cars
against ultraviolet radiation. Certain goods such as chemicals can be corrosive. Thus,
internal corrosion of the railroad cars can be prevented by using coating systems and
rubber linings for internal surfaces. Coatings and linings not only prolong the service
life of the fleet, but also preclude the contamination of the transported commodity by
a corroding metal surface. Corrosion prevention measures are of absolute necessity
particularly when transporting corrosive goods such as chemicals. The largest seg-
ment of the freight has been coal, chemicals and allied products transported, while
food and kindred products make up only 5% of the transported goods. These two
groups of commodities are either corrosive or sensitive to corrosion. Nearly 130,000
of covered hopper cars are used in transporting plastic pellets, which require liners to
preserve product parity. The life of a liner is 8–10 years.