Catch a Ride (Borderlands: The Pre-Sequel)

Travel to the farthest east Air Dome Generator platform. You reach it by jumping from the central platform to the roof on your left and jumping to the eastern roof at which point you take two jump platforms.

http://i.imgur.com/AthlAy7.jpg

Look north and down off the platform, you'll see 4 sets of tracks. Any of them work. Jump down to a rail, run down to the end of the track and wait for a tram to arrive at the bottom. Drop down onto the top of the tram and wait for it to ascend all the way to the top. You may want to hold crouch to avoid getting your head caught on the tracks as you ride the tram.

The challenge completes when the tram is stationary at the top end of the track.