(Photo by Gary)
Here's some additional detail about a side run I like along a trail just off (south of) the abandoned Turnpike. You go up a marked trail called the Railroad Arch Trail, signed along Oregon Road just west of where it crosses under the old Turnpike. It's a pleasant trail and an easy run on good footing. After perhaps half a mile all of a sudden you come upon a culvert containing a stream some 10' wide. The culvert is about 200' long, obviously old and carefully made of cut stone. It's intact--you can see from end to end and even walk through it if you don't mind wet feet.
Here's the official PA Department of Natural Resources blurb:
The Oregon Road area also includes a stone aqueduct built in the 1880s by masons brought from Sicily for an aborted railroad project. The aqueduct is 15 feet high, 10 feet wide, and 199 feet long and is easily accessible from Oregon Road on Railroad Arch Trail. Built with native stone without mortar, the Sicilian masons created a structure that is as solid today as the day it was built. The South Penn Railroad project also created the nearby tunnels that were used by the PA Turnpike before being abandoned in 1970. The tunnels can be reached by walking the abandoned turnpike, which is open to hiking and biking. A parking lot on Oregon Road is adjacent to the abandoned turnpike.
This culvert is a WAY cool bit of construction...but it is WAY out of place sitting here in the woods, with no clue as to why.
It took a return trip when the leaves were off the trees to figure out this engineering puzzle. See, this little stream flows down a wide ravine that is pretty much north-south, with the uphill end to the south and the downhill end towards the north (where the abandoned Turnpike is). The culvert runs parallel to the ravine. The unfinished South Penn Railroad that once was planned to occupy this route had to cross the ravine at right angles (i.e., east-west). Rather than build a trestle across, they were going to fill the ravine to build the embankment up to the height of the existing grade...which you can see when the leaves are off on the ravine's east side. The grade is above you some 30'? 40'? Maybe even 50', I can't recall.
But basically the culvert, some 200' long, would have been the width of the fill at the base. The fill would have tapered up like a trapezoid in cross-section, rising the 30' to 50' needed to reach grade level at appropriate railroad track width (maybe 20' or so wide?).
When you climb up and stand at on the east side of the ravine you can look down on the culvert and it all becomes pretty clear. You can imagine the grade where you are standing extending across the ravine at the same level, which would have been some big fill job. You can see the culvert that would have been buried in the bottom of the fill to carry the stream under the fill (else you have just a big earthen dam). You can also follow the old RR grade back east towards the abandoned Sideling Hill tunnel to where it's obliterated by the grading of the Turnpike.
The way this would have been solved today in railroad or highway engineering would be to install a 10' diameter pipe in lieu of all that stone work. Then just fill over it. Done.
But I like the stone arch and the forgotten Italian hands that crafted it.