The biggest story in transportation for the D.C. region this year will be the opening of Metro’s Silver Line. In fact, it’s among the biggest transportation stories in the nation.

While the debut holds center stage, it will renew a debate about whether the line should have been built and whether transit is an effective way of solving transportation problems.

It’s high-concept stuff. But so far, the questions coming in from local travelers are more like: “What’s the Silver Line?” They’re either asking what the new thing is or indicating confusion about what they’ve heard.

The success of this enormous investment in mass transit depends on the masses knowing how they can use it.

One question that came in for my online chat about the Silver Line on Monday may serve as an example.

Metrorail But Not Built By Metro? Is this line similar in nature to the MARC, but it just happens to run parallel to the Blue Line in some parts, use the same rails and stations to the Blue and Orange lines?”

Such confusion is inevitable, given the long, winding road this project has followed. With questions like that in mind, here’s a basic guide to the Silver Line.

It wasn’t built by Metro. This is the first part of the Metrorail system not built by the transit authority, although transit managers have been involved in the lengthy planning and construction process. The Metro board has voted several times to accept the project, most recently June 26.

It is part of Metrorail. Knowing that the new track and the five stations in Fairfax County were not being built by the transit authority led some travelers to think the Silver Line would be a separate service. In fact, riders won’t change trains to join the rest of Metrorail. And they can use their Metro SmarTrip cards to pay the fares. The fare rates are the same as in the rest of Metrorail.

Becoming part of Metrorail also means the new line will share some of the maintenance problems.

“The Silver Line will be maintained just like every other line on the system,” Metro Assistant General Manager Lynn Bowersox said.

“While the 11 or so miles of the Silver Line [in Fairfax] are new, the line also includes some of the oldest track on the system, and that rebuilding will continue. So, expect that Silver Line service will be adjusted on the weekends — just like Orange and Blue — as we advance this important work.”

It’s not just five stations. Eastbound Silver Line trains will join up with the original Metrorail system before East Falls Church and will end their trips at Largo Town Center. So if you’re bound for Metro Center from Largo and the signs on the rail cars say “Silver Line,” that’s your train.

New rail cars aren’t Silver Line cars. Travelers sometimes refer to the next generation of rail cars as “the Silver Line cars.” Metro is buying some of these 7000 series cars to accommodate the demand created by the Silver Line extension in Fairfax. That doesn’t mean they will run exclusively on the Silver Line. In fact, new rail cars can’t be reserved exclusively for one line.

And none will have entered service in time for the line’s scheduled opening.

As riders know so well, old Metrorail cars break down and are taken out of service.

They are just as likely to break down on the Silver Line as anywhere else in the rail system. That could happen to a Silver Line train at the new Tysons Corner station or at the old L’Enfant Plaza station.

This part doesn’t go to the airport. This first phase of the Silver Line, the part opening July 26, goes only as far west as the Wiehle-Reston East station on 11.4 miles of new track.

To reach Dulles International Airport, riders will need to transfer to buses, which will charge their own fares.

Travelers also ask the flip side of this question: “Does the Silver Line just go to the airport?” The first phase includes four stations in Tysons Corner, in addition to the end-of-the-line station at Wiehle Avenue, on the east side of Reston.

It won’t necessarily save time. How practical this new route will be for individual travelers depends on their starting points, destinations and the time of day for the trips.

A rush-hour ride from the west end of the line to Metro Center should take 41 minutes and cost $5.90, if you’re using a SmarTrip card to pay.

Some drivers along that corridor in Fairfax say the time and expense of rail travel won’t be worth making the switch.

A rider who is used to going to the West Falls Church station to catch a bus directly to Dulles asked what’s in this for her. When the Silver Line opens, she will have to go to the East Falls Church station, board a Silver Line train to Wiehle-Reston East, then board a bus to complete the airport trip.

Dr. Gridlock also appears Thursday in Local Living. Comments and questions are welcome and may be used in a column, along with the writer’s name and home community. Write Dr. Gridlock at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071, or
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