That's the one! Closed in 1956 as a commercial operation, sold to Kovalchik the local scrap dealer but all left in place as on the last day. The Kovalchik family operated a four mile section as a tourist attraction from 1960 to 2009 and then leased the line for two years to a preservation society, after which the Kovalchiks wanted to dispose of the railroad and it all got legally and commercially difficult. It all looks better now, with a non-profit company taking over in 2020 - I think a few diesel trips were run last year, but things are now looking a lot brighter in the long term and two Mikados are ready for operation this year.
I went there in 2000 and rode the tourist train. The railway really was the most extraordinary thing. The 27 miles of main line track is still there but totally overgrown in places, with coal hoppers rusted in place in the Mount Union yard and bears said to be resident in the tunnels. The rolling stock is straight out of the early 1900s and in original condition. If you are into narrow gauge and in Pennsylvania - it's about half way between Pittsburgh and Philadelphia - it's well worth the drive!
The roller shutter door was to prevent the wind blowing through the Sideling Hill Tunnel and freezing the water dripping from the roof, with predictable results for adhesion. It was opened by the driver pulling a chain on the approach and closed by the conductor. I understand a train did demolish the whole thing on at least one occasion.
Your set of very rusty rails.