Rhetoric about Amtrak usually is louder than the trains themselves, obscuring the crucial role that passenger service plays in the economy. A new report shows that is true especially in major metropolitan areas.

The Brookings Institution report found that Amtrak ridership increased 55 percent between 1997 and 2012, exceeding rates of increase over the same period for miles traveled by car, 16.5 percent; number of airline passengers, 20 percent; and number of transit riders, 26.4 percent. The number of passengers using the other modes was higher than for rail, but the increase for passenger rail demonstrates its growing importance.

The increases included 300 percent for Harrisburg-Philadelphia, 60 percent for Seattle-Tacoma, Wash.; and 64 percent on routes connecting Chicago, Detroit, Milwaukee and St. Louis.

Growth was especially robust on relatively short routes between major metropolitan areas, and among rapidly growing metropolitan areas, such as Raleigh-Charlotte, N.C., and Oklahoma City, Okla.-Dallas Fort Worth.

All of those routes were established with a combination of state and federal subsidies.

Critics lambaste that spending, but passenger rail is subsidized to some degree everywhere in the world. And the calculation should include the money that rail saves in terms of pollution, congestion and other forms of infrastructure that it replaces, especially highways.

The report points to rail's strengths and should help guide its continuing growth to bolster the economy and fight pollution.