It is not going to open for a while yet. Have to wonder just what happened inside the tunnel. It can also mean Pan Am is finding additional spots that may be prone to collaspe ?. Maybe tunnel roof has sagged ? Need a good report to squash my speculation.
Was Hossiac lined or left in ‘as dug’ condition?
Here’s the story from a local paper. It looks like a portion of the tunnel liner near the west portal has collapsed. Since the tunnel is 4.75 miles long I doubt the whole tunnel’s lined, most likely it’s only lined for a distance from the portals.
http://www.recorder.com/a1-hoosac-tunnerl-collapse-BE-SATURDAY-32695841
Keeping the 15" roadheader exercise from several decades ago in mind, wonder if water mechanical action did a number on the parent rock behind the liner (ungrouted - due to its age). The concrete & Stone brick failed with age and the crumbling, ungrouted rock behind the liner pushed it out* by vibration and pure weight.
Photos of the approaches make them look like swamps - constant condition? Steel sets configured to what they want for future clearance as the solution? ($$$ to an outfit essentially cheap, will NS help pony up?)
*with water as a lubricating/mechanical agent, especially in winter.
Geologic conditions through the 4.75 mile long tunnel are quite variable - ranging from hard rock to essentially sand - as I recall from the main book on the subject, A Pinprick of Light:
https://www.amazon.com/Pinprick-Light-Greenfield-Railroad-Hoosac/dp/1881535177
See also https://www.amazon.com/Builders-Hoosac-Tunnel-Cliff-Schexnayder/dp/1942155077
It’s always had a problem with water drainage - there are several small streams that flow down the mountain over top of it (including Tunnel Brook right over the western portal). Also, it looks like a swamp at the east end becasue Cascade Brook is right next to the track. Also, no one has ever done a basic drainage project to pipe it away, esp. at the eastern end - it’s not far to the Deerfield River, 600 ft. +/-. The tunnel no longer has doors, so a recent cold snap up that way could have caused more freeze-thaw cycles - same action that causes potholes in roads - which led to the rockfall.
See the photos at this website: https://www.atlasobscura.com/places/hoosac-tunnel
More information - such as the length of the damaged area? - would be helpful.
- PDN.
Latest bulletin from NS. Mid March for tunnel to reopen. However NS has arranged for detour traffic for allmost comodies including auto carriers. Ayer traffic still embargoed is Auto and intermodal. There must be a real problem inside the tunnel bore ? Sure would like some one to be a fly on the wall !
http://www.nscorp.com/content/nscorp/en/service-alerts/hoosac-tunnel-service-disruption.html
Is it possible that the tnnel reopening delay might be for making it domestic double stack capable /? Or is it already capable. Pan Am’s clearance diagram does not show the route domestic double stack capable .
I wonder if any of it is related to this 1979 story on steel liner.
Further reading in the B&M archives indicates this was not exactly a ‘steel liner’; it was little better than corrugated tin roofing material, and was used as an in-place form for tremie concrete … against 13 courses of who-knows-how-deteriorated brick in the ‘wet’ part of the tunnel.
Much of the rest is ‘rock’ with no liner apparently needed up to the late '70s … to hear them tell it at the time.
I do have to think that deteriorated concrete and rusty thin metal, almost certainly without any sort of bonding to the brick, is going to be a big piece of the puzzle here.
The problem is most likely where the steel liner isn’t. Geology is fickle and unpredictable. The response and the contractor equipment used will speak volumes. Local geologist or national tunnel expert/ consultant calling the shots? And how good are the rcords for the past 50 years and did ST/B&M keep the records (or did some lowlife operating manager (in this case PanAm/Mellon) deem those records not important to keep?)
To answer your question, most of the length of the tunnel is unlined. I know that because of a 'youthful indiscretion" where I and two college friends bicycled through the tunnel on the service road next to the tracks. Remember that there were originally two tracks in the tunnel, but it was reduced to one track in the middle to gain enough clearance for piggyback traffic - henc room enough for a road next to the tracks.
I just saw an infra red camera video today and I did not see any lining but might have missed it. Good video.
Just saw a drone video. Big hole in the ground.
Rich
Water continually flows out both ends of the tunnel due to water penetrating into the tunnel from above. The west end of the tunnel is lined with brick for a while and it occasionally falls in. Also there isn’t really a service road next to the tracks.