Pinkerton Tunnel

somerset | Fort Hill, PA Mile 51.9

The Nuts & Bolts: Pinkerton Tunnel

  • 849 feet long
  • Original Construction: completed in 1912
  • Rebuilt for GAP Use: 2015
  • Total Cost: $1,970,000.00
  • Engineer: Gannett Flemming (Paul Lewis, PE)
  • Contractor: GEO Build (Jack Hiller)
  • Project Managers: Jack Paulik, Brett Hollern

Trail builders had many challenges in redeveloping the infrastructure along the Great Allegheny Passage (GAP) and the Pinkerton Tunnel was no exception. The Pinkerton Tunnel project had many variations before the tunnel was finally fully rehabilitated in 2015. The restoration was repeatedly put on hold until the project was resurrected in the mid-2010s by Allegheny Trail Alliance (ATA) president Linda McKenna Boxx.

Two railroad tunnels were constructed through a peninsula in the Casselman River between Markleton and Fort Hill known as the Pinkerton Horn. The first, a timber-lined tunnel, was built by the Baltimore and Ohio Railroad (B&O) in 1871, only to be destroyed in a fire in 1879.[1] As a result, a 1.5 mile “shoofly,” or bypass, was built around the peninsula tunnel until repairs were finished.[2] The Western Maryland Railway built a second tunnel in 1912,[3] bookended by two bridges over the Casselman River – the Pinkerton Low Bridge and the Pinkerton High Bridge. However, this tunnel would fall into serious disrepair by the time all three Pinkerton structures were acquired by Somerset County in the early 1990s.

Once Somerset County purchased its section of the defunct Western Maryland Railway right-of-way, thanks to Somerset County Rails to Trails Association (SCRTA) co-founder Hank Parke and Somerset County Commissioner Dave Mankamyer, began trying to solve the Pinkerton Tunnel problem. After the 7.5 miles of trail were opened between Rockwood to the Pinkerton Low Bridge in April 1993, bids to repair the Pinkerton Tunnel were solicited in November.[4] The reconstruction was bid at close to $100,000 dollars, but the project reached a stalemate as the hired contractor underbid the work that would really need to be done at the tunnel.[5]

“They were going to get the Pinkerton Tunnel done first before they did the Salisbury Viaduct. And, they actually had an engineering contract, but the scope of work was not – when the company went in there – they had the contract, discovered that the roof was in much worse shape than they had thought. And, they were talking about all kinds of big bucks to fix this thing. And, they finally backed out of the whole project. They didn’t have enough money to do it.

– Lincoln Van Sickel, August 2005.[6]


By May 1994, any hope of progress within the Pinkerton Tunnel literally crumbled as an 80-foot slab of rock fell from the ceiling of the tunnel.[7] In December, the decision was made to abandon the tunnel project, as an alternate route became a more affordable option.[8] The short-term solution was to build a mile and a half of trail around the Pinkerton Horn using the old B&O shoofly, thereby circumventing the deteriorated Pinkerton Tunnel.[9]  The tunnel was closed at  each end while other segments of the trail were completed and the easement for the Pinkerton bypass route was obtained. The 1.5 mile-trail loop around the Pinkerton Horn opened in 1995.[10]

Once the detour around the Pinkerton Tunnel was available, no more work was done to the tunnel for nearly fourteen years. In 2012, CSX, which now owned the B&O, wished to convert their tunnel at Pinkerton to an open cut, allowing for double-stacked freight cars, as part of the National Gateway Project. With the pending removal of the B&O tunnel and the enormous amount of overburden that needed a place to be spoiled, CSX bought the adjacent Pinkerton Horn property — on which the trail loop was constructed — as a dump site. But CSX needed to cross over Somerset County property, where the WM tunnel sat over 200 feet below. Somerset County officials made a deal to eventually take ownership of the horn property in exchange for granting CSX an overhead crossing. 

“I think we realized early on [CSX was] going to dig their tunnel regardless of what we said or did so we tried to figure out the best way to take advantage of that situation. But, the biggest, you know, the monkey wrench in that was we had an abandoned tunnel that we had kind of given up hope of ever redoing because we had a bypass on it. And, thanks to leadership with the Allegheny Trail Alliance’s president Linda Boxx who wanted to see the trail restored to the original right-of-way – we worked with the railroad to figure out a way to go in there.”

-Brett Hollern, May 17, 2019[11]


In the meantime, Linda Boxx had begun to eye the Pinkerton Tunnel as its final project.

When the trail was being completed to Pittsburgh (the final Gaps in the GAP), substantial matching funds were privately raised, expended, then reimbursed through state and county capital grants. That process left ATA with $1.5 million which Boxx wished to direct to the Pinkerton Tunnel. This had not been a priority, since there was an attractive bypass; but with funds now available, it rose up as a good use of the money.

The National Gateway Project forced the trail builders to hold off on any repairs to the Pinkerton Tunnel until the demolition of the very nearby CSX tunnel was completed. With extensive rock-blasting and massive dumps trucks running over the tunnel, Somerset County’s tunnel could have easily collapsed.

Once the detour around the Pinkerton Tunnel was available, no more work was done to the tunnel for nearly fourteen years. In 2012, the B&O Railroad tunnel, now owned by CSX, located to the north of the Western Maryland Railway tunnel, was to be converted into an open cut to allow for double-stacked freight cars,[12] and as part of the CSX National Gateway Project. With the pending removal of the B&O tunnel, CSX bought the adjacent trail loop property on the Pinkerton Horn, as a dump site. This prompted Somerset County officials to make a deal with the company eventually to take ownership of the property in exchange for allowing CSX to cross above the Pinkerton Tunnel to dump excess soil.[13] The B&O tunnel excavation was completed two years later in 2014.[14]

 “The project may have been what could cause it to be beyond repair. I mean, they were running Euclid Trucks [massive dump trucks] over top of it with daily, like, hundreds of trucks taking fill to the other side. But, one of the byproducts was they had to buy all the land that was the Pinkerton Horn and they immediately gave us ownership up to the 35-foot Horn bypass that had previously been under easement from the prior landowner. So, there was that benefit from the project even if we never did the tunnel, we now owned the bypass.”

-Brett Hollern, May 17, 2019[15]


Boxx again reached out to Jack Paulik to assist with the project and contacted the engineering firm that had worked on Big Savage Tunnel. Paul Lewis, P.E. of Gannett Fleming was eager to work on the project and proposed a design-build option with GF handling design and engineering and GEOBuild of Columbus, Ohio to undertake the construction.

One of the challenging aspects was that we had this money, but it was a county structure. And, we wanted to do a design build, we didn’t want to do a design package and put it out to bid because it would have driven the cost through the roof, [and] the timing. We thought we’re good to go and sort of at the 11th hour our county solicitor said, ‘Wait, this probably doesn’t jive with county code. And, I’m not sure I can defend this if anybody would challenge us on not going through the proper bidding procedures.’ We were able to make the case that it was emergency repair because the crown of the tunnel had a crack running its entire length. The county engineer went to bat and said, ‘No, this could fail if we don’t get to it now.

-Brett Hollern, May 17, 2019[16]


But then there was another holdup, this time caused, not solved, by the County’s engineer. Owen Beachy of the EADS Group, submitted the tunnel project for review in July 2014 under Pennsylvania Natural Diversity Inventory. The PA Game Commission screened the project and, because there were Indiana Bats, an endangered species, located in the vicinity of the project, a study would be required and no work tunnel work could begin until the following May.

Was the tunnel an important hibernaculum for an endangered species? Knowledgeable people thought not since the wind current through the tunnel would make conditions too cold for bats to survive through the winter. Paul g Wiegman, a Somerset County Rails to Trails Association member, and Paulik even staked out the ends of the tunnel at dusk to note bat activity, hoping they could prove their theory and move forward with the project.  Despite observing very little bat activity, the study had to move forward.

Happily, six months and $25,000 later, the report indicated that the tunnel was indeed not a good place for bats to winter-over.

Finally, construction began, which consisted of inserting a corrugated steel liner along a foundation, then backfilling the voids with cellufoam, much like “Great Stuff” available for insulation at hardware stores. It was pumped into the voids between the liner and the bedrock above to prevent rocks falling on the liner. It filled “all the cracks and crevices and seals the tunnel up.” 20

The Pinkerton Tunnel rehabilitation was completed in 2015, reopening to pedestrians and bikes in September. The once abandoned and avoided structure was reborn for the public to enjoy, thanks to the trail builders who devoted their time and efforts to repurposing another major railroad infrastructure along the GAP.


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Author: Reed Hertzler