PA51 and Streets Run Rd -- Willock & Option, Allegheny County, PA
Adam Prince talks finding the old alignments of PA51 here and mentions the truss bridge over the railroad near Streets Run Rd. Not one to resist the curiosity...or the challenge, here's what I found.
From the 1939 "cloverleaf" grade separation at (New) Lebanon Church Rd / (New) Curry Hollow Rd, PA51 ascends the hill to possibly its highest elevation in Allegheny County. It passes under the steel girder bridge with Norfolk and Western RR prominently lettered. This line connects with the former Pgh and WV RR and the Montour RR into the South Hills and West End; to the northeast it links to the Union RR in the Mon Valley.
[There are old and new alignments of both Lebanon Church Rd and Curry Hollow Rd.]
After crossing the high point the current PA51 starts down hill toward the intersection at Streets Run Rd. This intersection is built on fill taken from various hillsides which were cut away to build the current PA51 route. The older intersection of PA51 and Streets Run Rd is a few hundred feet north: a crossroads with several old building which have been poorly maintained since the new road bypassed them. This intersection sits near the top of the Streets Run valley. Much of this part of the valley was owned by the Pittsburgh Mining Company and is referred to as Willock on some maps. In 1923, the mining company established the Option Independent Fire Co. which is now part of Baldwin Boro.
The name "Option" comes from the Option Station which was on the Pgh and WV (NW) rail line near the intersection of Streets Run Rd and Brownsville Rd -- about a half a mile south of the fire station and near the natural end of the Streets Run ravine. When the original PA51/Old Clairton Rd passed through the area, it appears that the descent from the Clairton Rd / NW rail crossing was not as gradual nor as straight. (Records show the URR being built in 1917, including a spur which ran along the current Pleasant Hills Blvd.) There are several cuts and fills which changed the lay of the land in this stretch. And what looks like an obvious straight path today must have been daunting then. If you look at the cuts as they exist today, they indicate the Streets Run valley split into several fingers just south of the old intersection of Streets Run and Old Clairton.
The Baltimore and Ohio RR followed the gradual incline of the creek valley up to this point and opted to bore a tunnel -- through the rise which carries the NW -- and exits in Curry Hollow behind Curry Hollow Centre. The .375 mile long tunnel has brick faced portals and a single track which crosses under (New) Curry Hollow Rd via a 1930 county bridge south of the "cloverleaf", passes near the 1782 log cabin of Jacob Beam and the 1800 stone and log house of John Work, on the way toward Cochran's Mill and points south.
The current PA51 crosses above the northern tunnel portal -- well hidden and ignored by traffic. A few hundred feet north from the tunnel Old Clairton Rd avoided the upper reachs of the Street Run valley and made a slight angle to the north to follow along the B&O as it cuts into the hillside toward the tunnel opening.
Where the hillside eventally narrows, the old road makes a left turn onto a metal truss bridge. The bridge is closed to all traffic including pedestrians (Bridge now removed). Older signs has a 3.5 ton limit posted, but now Jersey barriers block the road from both sides. The bridge is probably too new to be iron, but the construction details are certainly old enough to be from the very early 1900s. (Records show the railroad was taken over by the Baltimore and Ohio in 1883. The line was chartered by the Pittsburgh Southern in 1876.)
The top chord, inclined end posts and main vertical truss members are riveted lattice. The diagonal bracing and lower chord are pinned eyebars. It is a Pratt truss with 4 panels plus the inclined end posts. The deck is wood planks. The abutments are cut stone. On the western abutment, the lower portion has metal flanged beam supported angled against timbers. The angled supports are so rusted that they are more than 50% gone in some places. Heavy planks, at least 3"x6" are used for side rails along the deck. Guard rails leading up to the bridge are tall, thin pre-cast concrete posts with twisted wire rope between.
The road turns right at the western end of the bridge and passes what may have been a hotel or company store/office for the mining company. The valley northward is lined with "patch" housing -- rows of houses of the same design built for the workers. Missionary Rd dead ends on the western side of the B&O climbing up the valley; it seems that the road may have had a bridge which would have aligned with the gap between the standing buildings (east side of State Rep Harry Readshaw's office). Maybe a bridge here would have been a mine railroad or a street railway...more research needed.
The intersection of Old Clairton Rd and Streets Run Rd is some 50 feet lower than the newer intersection at PA51. It appears that Streets Run Rd continued southward past the PA51 intersection at a more gradual rate than it does today. As stated earlier, a great deal of fill has been added in this valley head and postwar houses line Streets Run Rd south of PA51 up to the location of Option Station at Brownsville Rd.
Old Clairton Rd continues westward from Streets Run Rd as a narrow asphalt path barely a lane-and-a-half wide. The backs of various buildings on new PA51 butt against the southern edge of the old road. The old road climbs out of the valley along one of Streets Run's fingers to meet the new road. At this intersection, a small pad of concrete indicates the former wearing surface of PA51.
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