On Tuesday, we featured the 120th challenge to see how well you know the Metro system. Here are the answers.

This week, we got 23 guesses. Six got all five right. Great work, Peter K, cceval, Nieto, Stephen C, Brian J, and AlexC!

Image 1: Vienna

The first image shows the south bus loop at Vienna station. The Fairfax Connector buses in the picture should have helped you narrow this down to one of the Virginia stations west or south of Arlington and Alexandria. The large parking garage could have helped you eliminate a few possibilities, like Van Dorn Street and Eisenhower Avenue, which don't have garages. You can also make out a “Q” on the bus shelter at far right. This may have helped you narrow things down farther. There's also a roundabout sign visible at left, which references the roundabouts built here as part of the station parking lot redevelopment, itself visible in the distance.

21 of you knew this one.

Image 2: Tysons Corner

The second image shows the canopy above the mezzanine at Tysons Corner station. This station is one of three stations with a gambrel style roof. However, you can easily eliminate Greensboro and Wiehle Avenue because at those stations, all of the entrances from the street enter the mezzanine at the same level, and this view could only be taken from the platform looking upward towards the exit. However, at Tysons Corner, there's a street-level entrance below the tracks. This view up the escalator includes a sign that says “SV Trains”, which can only be the case if you're entering the station from below the mezzanine. Only Tysons has this configuration.

15 got this one right.

Image 3: Twinbrook

The third image shows a view looking west from the platform at Twinbrook. In addition to being able to see the “gull I” roof, you can also make out a few of the buildings in the background, including the Hilton. The quiz from week 67 also featured a view of this Hilton.

20 guessed correctly.

Image 4: Pentagon

This picture of Pentagon station shows a view of the upper level looking toward the station's exit. The station is a split-level design like Rosslyn, which allows the train tracks to diverge immediately beyond the station without crossing over each other in a flat junction. While Pentagon and Rosslyn are nearly identical, there are some key differences. In this case, Pentagon does not have a fare control mezzanine. Instead, the faregates and station manager's kiosk are located on the same level as Largo and Mount Vernon Square trains. At Rosslyn, fare control is at street level. In this picture, you can see the kiosk, and therefore, this must be Pentagon.

Also, you can easily tell that this is one of the split-level stations because of the length of the “mezzanine”, which in this case is actually the upper platform, and the s-curve of the wall on the right side of the photo, which doesn't match any floating mezzanine walls at the traditional island or side platform stations.

14 knew this was Pentagon.

Image 5: Farragut West

The final image shows a view of Farragut West from the western (18th Street) mezzanine. This one was definitely harder than the others, and required you to use some deductive reasoning. The two key pieces of information you needed to solve this one were the station's platform configuration and the location of the elevator.

From the sign visible in the image, you can see that this is a station served by the Blue, Orange, and Silver lines. There are only three stations on all three lines that have side platforms: Farragut West, McPherson Square, and Smithsonian. This must be one of those three stations. But which one?

The elevator location is crucial to figuring this out. At McPherson Square and Smithsonian, the elevator is located at the Maryland end of the station. At Farragut West, it's at the Virginia end of the station. From this vantage point, we're next to an elevator at the end of the station where the track directly under is headed toward Franconia, Vienna, and Wiehle Ave. That means we're at the western end of Farragut West. From this vantage point at McPherson Square or Smithsonian, the sign would need to say Largo and New Carrollton.

11 of you came to the correct conclusion.

Great work, everyone. Thanks for playing! We'll be back soon with challenge #121.

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.