Paul_D_North_Jr When I have an opportunity, I'll post a photo or two of mine from last April or so of the Gwynedd Cut, formerly the Gwynedd Tunnel, of the Reading RR - now SEPTA, about a mile southwest of the Borough of North Wales, PA - at Lat. / Long. N 40.19674, W 75.26733 per the "ACME Mapper 2.0 " application. It was a shallow tunnel - well less than 100 ft. cover - when first bored through loose sedimentary rock in the mid-1800's as part of the construction of the North Pennsylvania Railroad/ branch, but was 'daylighted' circa 1930 as part of the electrification of the Reading's suburban lines to provide sufficient overhead clearance for the catenary wires and high-voltage transmission poles above. Recently SEPTA was installing chain-link fencing and shot-creting/ 'guniting' portions of the sides of the resulting cut to reduce the incidence and extent of the rockfalls, esp. during freeze-thaw cycles, and that's when I took my photos one evening. It's a good illustration of the points made by several other posts above about rock competency, groundwater effects, and by cx500 about how a cut should and must be wider than the tunnel it replaces. (As a philosophical aside, that may be another instance of the ironic "the perfect is the enemy of the good", which here translates to in a wordier form to an apparent improvement being stymied by the contra-principle of "the perfect solution conforming to all current standards is the enemy of a better solution than the existing crummy situation".)
It was a shallow tunnel - well less than 100 ft. cover - when first bored through loose sedimentary rock in the mid-1800's as part of the construction of the North Pennsylvania Railroad/ branch, but was 'daylighted' circa 1930 as part of the electrification of the Reading's suburban lines to provide sufficient overhead clearance for the catenary wires and high-voltage transmission poles above. Recently SEPTA was installing chain-link fencing and shot-creting/ 'guniting' portions of the sides of the resulting cut to reduce the incidence and extent of the rockfalls, esp. during freeze-thaw cycles, and that's when I took my photos one evening. It's a good illustration of the points made by several other posts above about rock competency, groundwater effects, and by cx500 about how a cut should and must be wider than the tunnel it replaces. (As a philosophical aside, that may be another instance of the ironic "the perfect is the enemy of the good", which here translates to in a wordier form to an apparent improvement being stymied by the contra-principle of "the perfect solution conforming to all current standards is the enemy of a better solution than the existing crummy situation".)
Selected photos below. Commentary later when I have more time. Enjoy ! - PDN.
Murphy Siding Page 73 of the January issue of Trains Magazine shows a Westbound BNSF Railway stack train fololwing the Flathead River through tunnel #4 in West Glacier, Montana. The tunnel appears to be as long as, say, 6 or 7 railcars. The amount of rock above the cars is perhaps 3 times the height of a loaded double stack car. The rock on the river side of the tunnel looks to be 2 to 3 times the width of the tunnel opening. Why would the builders have gone through all the work of building and maintaining a tunnel ,that looks like it could have easily been daylighteed?
Page 73 of the January issue of Trains Magazine shows a Westbound BNSF Railway stack train fololwing the Flathead River through tunnel #4 in West Glacier, Montana. The tunnel appears to be as long as, say, 6 or 7 railcars. The amount of rock above the cars is perhaps 3 times the height of a loaded double stack car. The rock on the river side of the tunnel looks to be 2 to 3 times the width of the tunnel opening. Why would the builders have gone through all the work of building and maintaining a tunnel ,that looks like it could have easily been daylighteed?
In addition to the technological limits of the time you also have to consider the state of the railroad busines back then. Since obviously things like Double Stack Intermodal trains, Autoracks, and Superliner passenger cars didn't exist yet and nobody fathomed of their existence they figured that as long as it provides clearance for the equipment around at the time no sense going to all the extra work.
Consider the 'grand-daddy' of all tunnel 'day-lighting' projects - the Southern Rwy.'s gradual elimination of all but 1 tunnel on the former 'Rathole' division of the Cincinnatti, New Orleans & Texas Pacific / Cincinnatti Southern line, which is described in this article from the Southern's "Ties" magazine titled "90 Years to "Daylight" ": http://southern.railfan.net/ties/1963/63-8/daylight.html
See also the messages on the forum about "Abandoned Rathole Tunnels" at this link: http://www.jreb.org/ns/index.php?topic=91.0
Finally, here's a link to a recent Steve Schmollinger photo of the Kings Mountain Cut, which bypassed one of the early 'Rathole' tunnels (No. 1 ?) as part of the early 1960's improvements. M-O-W people on other railroads that have cuts and tunnels to maintain have been known to cry ( ) when they see photos of cuts like this one - and the few new tunnels have almost as impressive overhead clearances:
http://www.railpictures.net/viewphoto.php?id=342451
- Paul North.
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