The Sept. 5 Metro article “Water troubles on the Red Line” suggested that water leakage along a Bethesda section of the Metro rail system is occurring “because that portion of Metro was built in the 1980s, when engineering practices were not as advanced, [so] there is no protective waterproof liner.”

I was the structural engineer involved in the design of the University of Maryland’s Hornbake Library, constructed about 40 years ago. There is a large reading room, located below a plaza that has roadways, parking and landscaping, all exposed to the weather. I called the university archivist and was told there has not been any significant water leakage since its construction. There are many other underground structures, such as tunnels and parking garages, built even earlier, that have successfully resisted water intrusion.

Whatever the cause of the water leakage on the Red Line, the lack of advanced engineering practices is not the problem.

Thomas Carcaterra, Silver Spring