Metro’s new Silver Line is one of the largest transit projects under construction in the country, bringing with it new trains, new destinations, even a new color to the region’s subway system.

Last week, riders got to see the new Metrorail map showing the actual line for the first time. And by the beginning of next year, they should be able to ride trains on it.

But the Silver Line, heralded as it is, may actually make Metro worse for riders in the short-term.

Yes, the first 11.6-mile section will finally make the bustling, car-centric Tysons Corner hub of retail and jobs accessible by train. The rest of the 23-mile line should connect to Washington Dulles International Airport and Loudoun County by 2018. In doing so, the project will expand the Metrorail system by 22 percent, in the biggest single addition to the system since it was built.

Except that the new line will also funnel more riders into the crowded downtown stations of a burdened and aging transit system that currently struggles to keep up with a backlog of repairs. The line is expanding the mouth of the bottle but not the neck. Any Metro rider during rush hour has seen the packed platforms downtown and waited in line to climb frozen escalators—now add more people.

The new line will also reduce service for some riders, because Metro is cramming another Virginia line into a tunnel under the Potomac River that literally cannot fit any more trains.

And the expansion may be coming before the rail system is actually ready. Service systemwide will likely be less reliable for years to come, because Metro won’t complete an expansion of its fleet of train cars until at least 2017.

It may also be coming too late to reform ungainly Tysons and to resuscitate Dulles Airport, which is already losing passengers to more accessible rivals.

For all this, the system’s cost per passenger will likely rise, leaving riders and taxpayers around the region to pay the bill.

Even if you never take the Silver Line, it’ll affect your regular Metro trips once it begins operating. Commuters already know how a single broken door can force a train out of service and foul up a morning commute along the whole line. The train cars that run on the system are old and temperamental, sometimes even stinking of mildew. Now imagine those same rail cars spread even thinner around the system than they are today. In the short term, the transit agency is planning to cover more ground with that same fleet of trains.

Metro has ordered 128 new rail cars to accommodate the Silver Line expansion but, except for four test cars, the reinforcements won’t begin to trickle in until around next August. The last of those new cars aren’t scheduled to arrive until 2017. And each new car needs to undergo extensive testing before it can be put into service.

Even as the new cars begin to arrive, Metro also faces a trade-off between safety and service. The National Transportation Safety Board has repeatedly told the transit agency to scrap its oldest generation of rail cars, the Rohr 1000 series. That model crushed like soda cans in the 2009 Red Line crash that killed nine people. Metro has ordered 300 cars to replace those 1000 series cars, in addition to the cars for the expansion. But as each new car arrives, Metro will need to decide whether to expand its fleet or to retire one of the old, less safe cars.

Already, the agency has been reducing the number of cars it keeps in reserve, limiting its capacity to quickly replace cars with broken doors or other problems. The transit agency has about 1,120 rail cars. Last year, Metro operated about 770 of those rail cars in daily service. Recently, Metro increased the number to 906 cars daily. Once the first section of the Silver Line opens, the agency has said it will need 954 cars in daily service. That leaves less than half the number of spare cars that were available about two years ago.

Metro says better maintenance will allow it to skate by with fewer cars in reserve. “Simply put, we will have sufficient cars to support Silver Line operations,” Metro spokeswoman Caroline Lukas says. But those cars will have to remain extra-reliable for years until the new cars can fill the void.

Meanwhile, some riders—including Northern Virginians, who are paying for much of the nearly $6 billion cost of building the new line—will see their existing rail service diminish. Literally no more trains can fit through the Rosslyn tunnel that bores under the Potomac River, so something needs to give to fit the new line.

The so-called Rush Plus campaign launched last summer was the first stage of the change, with the agency rerouting some trains during peak hours. Riders to and from the Virginia end of the Blue Line got longer waits and more crowded trains. Once the Silver Line begins, the frequency of Blue Line service there will be reduced further from an average of every 8.5 minutes to 12 minutes throughout the day, according to Metro.

Lukas insists this isn’t a “net” service reduction. “Riders at stations along the Blue Line will see trains arrive as frequently as they do today, but more of them will be Yellow,” she says by email. “As many customers learned from Rush Plus, taking a Yellow Line train and transferring at L’Enfant Plaza may provide a faster trip.”

But riders haven’t been totally convinced that transferring from Blue to Yellow is better for them, despite Metro’s attempts to woo them with free ride credits.

The reduction in trains also hits some Orange Line riders. When the Silver Line begins, the extra trains borrowed from the Blue Line for Rush Plus to bolster service on the Orange Line will be diverted away from the western end of that overcrowded line, at the Vienna, Dunn Loring and West Falls Church stations. Riders there will wait, on average, 5.5 minutes between trains, instead of the current 3.5 minute average, the agency has estimated. Metro has said it doesn’t expect more crowding, though, as some existing riders will choose to take the Silver Line instead.

And everyone will be sharing in the costs of running the Silver Line—even if they never set foot on it.

While many Silver Line riders will likely pay the system’s highest fare, currently $5.75 with a SmarTrip card, that money won’t cover the whole cost for a ride. (For that matter, every ride on Metro is already subsidized by taxpayer dollars.)

The expectation is that the Silver Line will drive up the cost per passenger trip even more, in part because it’s a long, suburban line with stops that are relatively far apart. The most cost-effective lines generally run through already densely populated areas. Those who live in Maryland and the District will be helping pay to run the trains, either by subsidizing Metrorail more or paying higher fares. Or, conceivably, both.

So is the Silver Line worth the short- and long-term pain?

The new line will connect to Tysons, whose center of gravity as a jobs center is already swaying the regional economy. Stewart Schwartz, executive director of the Coalition for Smarter Growth, notes that the expansion will make it easier for District residents who don’t have cars—by choice or by income—to get to those jobs. That’s a real concern in the city, where unemployment remained 8.9 percent in June, more than twice the rate of Arlington.

That creates the chance for Metro to capitalize more on reverse-commuters filling seats on the near-empty trains out of the downtown core each morning as they head to Tysons Corner, making the system more efficient. And the line could mean fewer roads needing to be built and less pollution spewing from cars stuck in traffic trying to reach Tysons. That could be good for everyone, since smog doesn’t stay on one side of a border.

But the Silver Line is effectively chasing development there, rather than being the catalyst for growth like the Orange Line was in Arlington. Transit advocates like Ben Ross—a leader of Action Committee for Transit, which has fought to improve Metro and local transit options for 27 years—are doubtful Tysons will end up easily walkable. Instead, he says, the development will be “transit-adjacent,” not “transit-oriented.”

The second phase of the line will eventually give riders the chance to take the train to Dulles. But it’ll take 52 minutes to get there from Metro Center, by the agency’s estimate. And that doesn’t include waits for trains or the time it takes to walk from the station to the airline terminals. (As a cost-cutting measure, the airport stop was relocated from the terminal to a parking garage.) Such a long trip may not be worthwhile for any but the most time-rich and cash-poor travelers.

Getting to Baltimore-Washington Thurgood Marshall International Airport, by contrast, takes as little as 32 minutes on a MARC commuter train from Union Station, not including the final connection to the airport terminals. MARC will run on weekends starting Dec. 7, becoming even more attractive for D.C. travelers. Ronald Reagan Washington National Airport is already an easy Metro trip for most in D.C.

“It’s something of a mistake to think of the Silver Line as providing a way to get to the airport,” says Zachary Schrag, a George Mason University professor who wrote a history of Metro. “It’s more important to think of it as an employment corridor.”

Groups such as the Coalition for Smarter Growth unsuccessfully fought plans to run the Silver Line down the center of highways, arguing that would make it much harder to goose development around the 11 stations.

“It will not achieve as much as it could have achieved,” Schwartz says.

Some of the downsides of the Silver Line’s construction might become more common in D.C.-area public transit in the future. Metrorail was designed to be regional, uniting the needs of the District, Maryland, and Virginia, while shuttling federal workers between their jobs and suburban homes. But the transit agency washed its hands of that high-stakes political poker game in 2007. It laid off the last of its construction and engineering crews and focused solely on operating the system, leaving any new construction up to the individual jurisdictions to undertake—and fund. That allowed a more parochial view to take hold.

Northern Virginia wanted another line, so it’s building one. Maryland wants one, too, so it plans to build the Purple Line. The District and Arlington want streetcars, while Montgomery County wants a network of bus lanes. All these separate plans could create a fractious transit system that leaves the region with lots of incompatible lines and different styles of train cars and trolleys that don’t work on each others’ systems.

Transit advocates and development planners are hesitant to publicly complain about the Silver Line, perhaps a testament to the vulnerability transit has faced politically. They’re trying to see the train car as half-full, even if the line means growing pains and uncertain outcomes. “The Silver Line is being built,” Schwartz says. “We should make sure it succeeds.”

Photo by Darrow Montgomery