On Tuesday, we featured the 107th challenge to see how well you knew the Metro system. Here are the answers. How'd you do?

This week, we got 22 guesses. Eight of you got all five. Great work, Justin..., Peter K, AlexC, Benjamin Nieva, ArlFfx, Stephen C, dpod, and Peter K is a nice guy, don't be hatin' on him! 

All the photos this week were based on a theme. Each picture showed a part of a direct station elevator entrance with its own faregate. Only a few stations fit the bill, so figuring out the theme should have helped you. Three of you identified the theme in your comments. Excellent detective work, Justin..., Peter K, and AlexC. 

Image 1: Judiciary Square

The first image shows the elevator entrance and faregate at the western end of Judiciary Square. The side platforms immediately narrow the field, since most Metro stops have island platforms.

You can also see that there's a crossover between tracks just beyond the station. A few underground side platform stations have crossovers nearby. McPherson Square, Dupont Circle, L'Enfant Plaza, and Pentagon City each have crossovers on the same end as their elevators, but none of those stations has elevator faregates on the platform. At Smithsonian, the crossover isn't visible from the platform, and is at the end opposite the elevator.

That leaves Ballston and Judiciary Square. One difference between these two is that at Ballston, the elevator is beyond the station end wall, meaning when the elevator doors open, you're looking down the platform. At Judiciary Square, the elevator is beyond the vault, meaning when the elevator doors open, you're looking at the tracks.

Also, you can see that the approaching train is a Red Line train. 15 knew the right answer.

Image 2: Arlington Cemetery

The second image shows the elevator entrance on the inbound platform at Arlington Cemetery. This station is one of the few unique station designs in the system, so it should've been fairly recognizable. 

The PIDS offers you two clues. First, these new type PIDS are only located at stations that have elevator-only entrances. Second, you can see that the station is served by the Blue Line. The only aboveground Blue Line station with side platforms is Arlington Cemetery.

18 got it correct.

Image 3: Ballston

The third image shows the elevator faregate at Ballston. The new PIDS is present, along with the platform faregate to tell you this station has an elevator-only entrance.

Additionally, you can see the back of the old terminal supervisor's booth, which dates back to when this station was the end of the Blue-Orange and Orange lines from 1979-1986. Several stations have vestigial "temporary" terminal supervisor's booths (as opposed to built-in ones like at Fort Totten (lower) and Silver Spring). However the only one on a side-platform station is at Ballston.

16 guessed correctly.

Image 4: Rosslyn

This picture shows a PIDS sign in the elevator-only entrance at Rosslyn. This station used to have a single faregate elevator-only entrance like at the other featured stations, but that elevator closed when the new eastern entrance opened. The new entrance has three elevators. The old elevator shaft still exists, but has been severed near ground level by a new development.

This one probably took some deductive reasoning to nail down. If you figured out the theme, it would have helped you narrow this down. You can also see the station is served by three lines.

The fresher concrete and newer (but not a full-color) PIDS was also a useful hint.

17 solved it.

Image 5: Minnesota Avenue

The final image was more difficult. It shows the elevator entrance within the mezzanine at Minnesota Avenue.

From context, especially the natural light, you should have gathered that this was an aboveground station with a mezzanine below the platform. There are many stations that fit the bill. But few have a separate elevator faregate within the mezzanine. Most of the stations with odd elevator arrangements opened before 1980, and the odd locations are because the stations were initially designed without elevators, and the designs were later modified to include them.

At Minnesota Avenue, which opened in 1978, that meant the elevator couldn't fit behind the line of faregates, so it was installed west of them, across the corridor. 

Brookland and Deanwood stations have a similar setup, but with one major difference. While the elevator comes down at those stations outside the faregates, it does come down on the same side of the corridor, meaning it is behind the grates that are shut when the station is closed. Here, the elevator has its own gate.

Additionally, the configuration of the mezzanine is mirror that of Deanwood and Brookland. At those stations, from the perspective of the wider main entrance, the mezzanine is to the left. But as you can see here, at Minnesota Avenue, it's to the right.

14 came to the correct conclusion.

Great work, everyone. Thanks for playing! We'll be back in two weeks with week 108.

Information about contest rules, submission guidelines, and a leaderboard is available at http://ggwash.org/whichwmata.

Matt Johnson has lived in the Washington area since 2007. He has a Master’s in Planning from the University of Maryland and a BS in Public Policy from Georgia Tech. He lives in Dupont Circle. He’s a member of the American Institute of Certified Planners, and is an employee of the Montgomery County Department of Transportation. His views are his own and do not represent those of his employer.