Here are the answers to whichWMATA week 115. How’d you do?

On Tuesday, we featured the 115th challenge to see how well you know the Metro system. Here are the answers.

This week, we got 17 guesses. Seven of you got all five. Great work, JamesDCane, AlexC, Peter K, ArlFfx, Stephen C, Solomon, and maxG!

The first image shows the northern entrance hall at Friendship Heights station. This circular room is a unique feature in the Metro system and connects four street escalators to the main shaft leading to the northern mezzanine. It was very distinctive, and as a result everyone got it right. Great job!

The second image shows the underside of the Memorial Drive bridge over Arlington Cemetery station. Arlington Cemetery doesn't have a canopy of its own; only the wide road bridge provides shelter from the elements. However, the underside of the bridge does have acoustical tiles and standard Metro globe lights, which makes the unique design fit into the overall design motif of the system.

15 of you knew the answer.

The third image shows the entry escalators at Cheverly station. We featured a similar perspective, taken by Peter K, in Week 38. The main clue here is the underside of the mezzanine/bridge to the platforms. The bridge is very distinctive, and we've featured it a few times, including Week 52. Despite being thin on clues, 13 of you guessed correctly.

The fourth image shows the top of the escalator shaft at Wheaton. While Metro has several stations that have very long escalator shafts, only Wheaton's and Rosslyn's emerge directly into a fare control mezzanine at the top. At the other stations, the mezzanine is at the bottom of the shaft. Rosslyn's mezzanine is quite different from this one.

14 of you guessed Wheaton.

The final image was the hardest, partially because it included a red herring. This picture is from Mount Vernon Square, not Van Ness, as many of you guessed. Based on the height of the transition between the lower coffer and the next coffer up, this has to be one of the five Arch II stations. At Arch I stations like Van Ness, the bottom coffer goes much higher. The other two clues are the signs, one posted on the station end wall and one posted just inside the tunnel.

The white sign inside the tunnel is an evacuation sign. These are posted at regular intervals in tunnels and give the number of feet and point the way to the stations in either direction. In this case, the top line is pointing evacuees to the Mount Vernon Square-UDC station. At one time, there were two stations with the UDC label. Before Mount Vernon Square became Mt Vernon Sq-7th Street/Convention Center, it was Mount Vernon Sq-UDC.

The main clue here was the other sign, in yellow and black. That sign, intended for train operators, indicates that they must use manual mode to enter all pocket tracks. And there is a pocket track just beyond Mount Vernon Square station. It's where Yellow Line trains turn around during rush hours.

Nine of you came to the correct conclusion. Excellent job!

Great work, everyone. Thanks for playing! We'll be back in two weeks with challenge #116.

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