The B&O's early engineers were overly concerned about keeping their
railroad level. They feared the steam engines would not be able to
pull loads on steep grades, so they restricted the OML to a mere 0.7%
grade. To keep things flat, substantial fills were needed at certain
locations, such as Gadsby's Run (also known as Herbert's Run).
Here a 57-foot fill was built over a small arched bridge.
As at the Deep Cut, all this work was done by hand.
This is the only B&O stone bridge to display 3 construction dates,
the oldest 1828, the next 1875 when it was widened to support more
tracks, and the third 19??. The final date is embossed in concrete
that has not survived as well as the adjacent granite, leaving its
last two digits tough to decipher. In an act of preservation,
for the 1875 widening the new portion
was built inside, and the original stone arch retained and moved
outward. It's easy to see this by walking part way into the tunnel.
In the foreground, an inexplicably odd assortment of rocks embedded
in concrete litters the streambed. This is one of the easiest OML
arched stone bridges to access. Simply drive to the end of Hollins
Ferry Road, and walk a short distance toward the stream.