In 1985, 7 U.S. cities had commuter rail systems. Today, 14 (including Salt Lake City, above) do. Those new starts differed in significant ways — especially in level of service — from the existing systems. But now we may be seeing a third generation of commuter rail. The good news is that it offers more frequent and more reliable service. The bad news is that it costs more.

The first generation systems — Boston, New York (below), Philadelphia, Baltimore-DC, Chicago, San Francisco — date from before the 1920s. Railroads never made money on commuters, but they made a lot of money as the dominant mode for freight transportation, so they could afford to spend money on passenger rail facilities. They also had an incentive to do so: the industrial executives who decided which railroad to ship their freight with were often commuter train riders, as were railroad executives’ friends and neighbors (it’s no accident that the cities with the best commuter rail systems were those with railroad headquarters.) This money bought excellent infrastructure: double, triple, and quadruple track, grade separations, flyovers at junctions, electrification, elaborate terminal stations reached through urban tunnels. That long-lived infrastructure still sustains those cities today.

The second generation systems were born in a different world. In the 1970s, the U.S. railroad system seemed on the brink of collapse. Some major railroads were in bankruptcy; others were weak. Industrial decline was taking traffic away from urban rail lines, trucks were taking much of what remained, and a series of mergers made many lines redundant. Railroad executives, having seen two decades of contraction, were in a cost control mindset. When transit agencies looking to build low-cost suburban transit looked for railroad lines, the railroads were glad to rent space on their tracks or sell lines outright. Sometimes, those sales were the only thing keeping weak railroads afloat.

Thus, second generation commuter rail was transit shaped by opportunity. The goal was minimal investment. This usually meant operating trains on single-track lines, using occasional sidings to pass other commuter and freight trains (as in Dallas, below). It meant simple stations (though many of the old downtown stations had survived to be reused), diesel power, and a lot of grade crossings. This was cheap. But, as usual, you got what you paid for. he old commuter rail lines in Chicago, Boston, and Philadelphia operate between 50 and 90 trains a day on over 10 lines each; New York has multiple lines with 100 trains a day. The second generation commuter lines often run only at rush hour, and only in rush hour direction. 10 to 20 trains a day are typical; some lines have only 8.

But the era that created second generation commuter rail has passed, too. Freight traffic is increasing; the railroads are dealing with problems of growth, not the problems of decline. Surplus rail lines are few and far between, and active lines don’t have much spare capacity. Railroads now regret the opportunities they lost in the line sales of the 1980s and 1990s, and, since they have no problem getting money from investors, they don’t need to sell lines for cash.

But the demand for commuter rail hasn’t gone away. In fact, it’s greater than ever, and more political support for transit means more federal, state, and local funding. That assure we’ll see more commuter rail. But it’s going to look different.

For a hint of the future of commuter rail, go to Utah. Ignore the empty deserts: Utah is surprisingly urban. Most of the state’s population crowds in a narrow strip along the Wasatch Front. The resulting traffic congestion is nonpartisan, and thus conservative Utah has become a major transit supporter, with 69% of Salt Lake City metro area residents voting to tax themselves for transit. But it’s also at the core of the Western railroad system, with Union Pacific lines radiating out to Los Angeles, San Francisco, Portland, Omaha, and Denver, and the intermountain west’s biggest industrial cluster surrounds those rail lines.

Thus, there were no spare freight rail tracks to be had. So the Utah Transit Authority bought a strip of land alongside the freight rail line from Union Pacific and built 38 miles of new passenger-only railroad from Salt Lake City to Ogden. Previous commuter rail lines have upgraded signal systems or added a few sidings. But there hasn’t been a new line this long since before World War II.

So what does $611 million buy, besides new tracks, 7 stations, locomotives, cars, and a 2,000 foot bridge to separate commuter rail from freight rail on the approach to Ogden?

It buys a lot of service. FrontRunner every 30 minutes in each direction all day long, from 4:00 AM to midnight. That’s 74 trains a day. And, since they are the only traffic on the railroad, they’re fast (79 mph) and on time. 30 minutes isn’t quite “don’t need to look at the schedule” frequency, but it gives riders a lot of choices: what to work late? Go home early on a Friday? See a basketball game at night? Commuter from Salt Lake to Provo rather than the other way around? No problem. It also buys “futureproofing”: add more tracks and you could run every 15 minutes.

But here’s a caveat: commuter rail is only a good deal if it goes where people want to go. Fast, frequent service to nowhere is useless. In older cities, commuter is integrated into the urban fabric. Downtowns grew around stations like Grand Central in New York, so passengers are dropped off within walking distance from work. Front Runner’s station is a mile from Downtown; it’s a convenient transfer to light rail, but a transfer nonetheless. In older cities, commuter rail is also integrated into the suburban fabric: stations are in town centers, a short walk from stores and residential neighborhoods. In Salt Lake, the stations are parking lots off of the freeway. Salt Lake’s TRAX light rail line extends from the center of Downtown 5 miles south to Sandy. That line cost $300 million to build; it exceeded expectations with 20,000 average weekday riders. After a $118 million extension to the university, the system now carries 53,000. FrontRunner cost more to build but carries only 4,800.

Still, Frontrunner may be the face of the future. Other cities face the same freight rail challenge. Houston commuter rail, for example, will require new tracks to get inside 610. New Mexico and Maryland have built new rail lines to go to places that didn’t have tracks before.

Frontrunner is also a flashback: this is the kind of rail infrastructure we were building 100 years ago. With dedicated tracks, flyovers, and frequent service, third generation commuter rail looks a lot like first generation commuter rail.