Today, Amtrak turns 40. This slideshow shows how passenger rail service has evolved over the decades, using maps from Malcolm Kenton and the National Association of Railroad Passengers.

On May 1, 1971, Amtrak replaced a much more extensive private passenger rail network that was on the decline due to massive government investment in other modes of transportation. It has struggled at times throughout its 40-year history, and some routes have come and gone, but it’s kept valuable rail service alive.

What remains of the national passenger train network, albeit skeletal compared to what it was and what it should be, exists largely thanks to the efforts of grassroots advocates who understand trains’ superior energy efficiency and the importance of having balance and choice in the American transportation system.

The National Association of Railroad Passengers organized in 1967 and built a broad coalition that lobbied successfully for the passage of the 1970 law that created Amtrak. NARP and its allies have successfully fought further contraction of the system ever since, and are now building support for long-term, dedicated federal funding for intercity passenger rail—something highways and aviation enjoy, while Amtrak has had to fight for its small share of general funds in every year’s appropriations cycle.