The milestone was the second time in just four months that it set a monthly record. Previously, it's busiest month ever was March, when it had just over 2.8 million riders.
"Amtrak is delivering record ridership across the country and serving as an economic engine to help local communities grow and prosper," Amtrak President and CEO Joe Boardman said in a statement.
The passenger-rail provider reported year-over-year ridership increase of 4.8 percent for July, with gains in its long-distance, short-distance and Northeast Corridor routes.
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According to a Brookings Institution study released earlier this spring, Amtrak has set ridership records for nine of the past 10 years. Amtrak officials say they're on pace to meet or exceed the annual ridership record they set last year of 31.2 million passengers.
The increased ridership comes at a pivotal time for the rail provider. The Passenger Rail Investment and Improvement Act, which reauthorizes Amtrak and sets federal passenger rail policy, expires in September. Some House Republicans will likely try to reduce federal funding for Amtrak's long-haul routes, which are not profitable.
Amtrak has advocated for the continuation of those routes, portraying them as an integral part of the rail network.
