This fine arched tunnel, stone faced with a brick interior, was built as part of the great Wabash Pittsburgh Terminal Railway boondoggle, one of the boondoggliest boondoggles in a city known for boondoggles.

Just off Saw Mill Run Boulevard is a little parking lot. You have to look for it: it’s on the turnoff to Woodruff Street, and it’s almost invisible till you’re right there. From there you can reach the arch, which is well worth a visit for its own sake. The interior in particular is more interesting than interiors of tunnels usually are. The engineers had fun with this one.

If you walk through the tunnel into the green world beyond, you’ll find that you’re walking on a broad path of gravel and occasional asphalt. This was Watkins Lane, the only way into a little farm village called Seldom Seen, or Shalerville before that. Like a surprising number of isolated bits of the city of Pittsburgh, it remained a farming village, with farming, even into the twentieth century. It was abandoned by some time in the 1960s, and the forest has reclaimed it. We’ll see more of Seldom Seen in the future.

Stream valleys in the Pittsburgh area are valuable as being the only nearly level routes through the landscape, and you will never find a major stream valley without railroad tracks in it. But as we can see here, the Saw Mill Run valley has had three railroads in it at once, one of which is still active.

In the spring Saw Mill Run is often a raging torrent, but it is much more placid in the summer.