jjdamnit Hello all, NYBW-John My preference would be to go with a tunnel because it will be a more effective scenic divider but I want it to be prototypical as well. Ahh...The classic dilemma! Just to throw this out there, From an operational standpoint a cut would allow you to re-rail any derailments. A tunnel would be more challenging. As has been mentioned, prototypically what is the geologic composition of the rock outcropping? Another point, that I don't believe has been made, is what is the time period you are modeling? The reason I ask; if you are modeling this area in the steam era- -when this obstacle might have first been encountered, a tunnel might have been the solution for that time. If you are modeling this same area, in a more modern time frame, perhaps the tunnel might have been too dificult to maintain and opened to a cut. You might think this scenario is farfetched but in modern times there was an incident where an entire line had to be rerouted due to a landslide on a cut. The situation I am thinking of it is the opposite of your quandary. The line was destroyed by a landslide along the existing cut and replaced with a tunnel. As a result, the line in the cut was abandoned. This could be a modeling opportunity. You could model the failed cut, with the abandoned trackage, next to the tunnel. Hope this helps.
Hello all,
NYBW-John My preference would be to go with a tunnel because it will be a more effective scenic divider but I want it to be prototypical as well.
Ahh...The classic dilemma!
Just to throw this out there,
From an operational standpoint a cut would allow you to re-rail any derailments. A tunnel would be more challenging.
As has been mentioned, prototypically what is the geologic composition of the rock outcropping?
Another point, that I don't believe has been made, is what is the time period you are modeling?
The reason I ask; if you are modeling this area in the steam era- -when this obstacle might have first been encountered, a tunnel might have been the solution for that time.
If you are modeling this same area, in a more modern time frame, perhaps the tunnel might have been too dificult to maintain and opened to a cut.
You might think this scenario is farfetched but in modern times there was an incident where an entire line had to be rerouted due to a landslide on a cut.
The situation I am thinking of it is the opposite of your quandary.
The line was destroyed by a landslide along the existing cut and replaced with a tunnel.
As a result, the line in the cut was abandoned.
This could be a modeling opportunity. You could model the failed cut, with the abandoned trackage, next to the tunnel.
Hope this helps.
I'm not too concerned about derailments in the tunnel. The approach on one side is a straight track and on the other is a gently curving easement. The tunnel is fairly short. In the unlikelihood of a derailment, it's not going to be terribly difficult to reach it from one end or the other. I have small hands so that helps. (Please no Marco Rubio comments).
My layout is set in 1956 but the history of the branchline was that it was built in the early 20th century.
Based on the comments, it seems a tunnel through this rock outcropping is plausible. Even though my layout is freelanced, plausibility is a priority with me. I don't like to fall back on the "it's your railroad" excuse. If it's not a prototypical practice, I don't want to use it on my railroad. I was happy to get arguments on both sides of the questions and it confirmed that in this circumstance either a tunnel or cut could be appropriate.
tcwright973 NittanyLion - I'm familar with the tunnel in your 1st photo. Before we were married, my wife lived about a mile away. I had to cross those tracks just south of the tunnel to date her. In fact, if you zoom left from the tunnel you will see a small church. That's the church we were married in 53 years ago. There is a 2nd tunnel south of yours which is very similar, perhaps a little bit longer. The Allegheny Valley Railroad operates over this track now, but I can recall when it was owned by the B&O, then the Chessie, & then I believe by the Buffalo & Pittsburgh. It's not too busy these days. Anyway, your post sure brought back a lot memories, so I thank you. EDIT - I should have included CSX in that list.
NittanyLion - I'm familar with the tunnel in your 1st photo. Before we were married, my wife lived about a mile away. I had to cross those tracks just south of the tunnel to date her. In fact, if you zoom left from the tunnel you will see a small church. That's the church we were married in 53 years ago.
There is a 2nd tunnel south of yours which is very similar, perhaps a little bit longer. The Allegheny Valley Railroad operates over this track now, but I can recall when it was owned by the B&O, then the Chessie, & then I believe by the Buffalo & Pittsburgh. It's not too busy these days.
Anyway, your post sure brought back a lot memories, so I thank you.
EDIT - I should have included CSX in that list.
Huh, isn't that something. I grew up in Butler not all that long ago, but remember when CSX was still moving strings of autoracks along there. I think its still technically B&P ownership, but AVR operates everything up to Eidenau. I used to be freelancing a version of reality that assumed Bantam had successfully won the Jeep contract, completely changing the economy of Butler County, and, 65 years later, a large regional sat in place of the B&LE, B&P, AVR, and everyone else. Now, I'm drifting more to prototype and might go all in on AVR.
Also: some years ago, the B&O Historical Society did a series about Pittsburgh operations and included very detailed drawings of those tunnels. If I ever get my sprawling basement, I'm going to give serious consideration to doing Butler to, oh, say Etna.
As for the Point of Rocks tunnel, what gets me is that it hasn't been cut back since the modern cut was made. From a naive standpoint, it looks trivial compared to some of the titanic efforts they made daylighting the bigger tunnels up the line. One of my Capitol Limited trips during the daylighting work actually went through a "tunnel" that consisted of exactly one portal, standing all alone.
Just as a practical matter - for modelling purposes - it would probably be easier to convert a cut into a tunnel than to "daylight" a model tunnel. So maybe try a cut first, if you decide you don't like it, won't be too hard to change to a tunnel.
NYBW-JohnMy preference would be to go with a tunnel because it will be a more effective scenic divider but I want it to be prototypical as well.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
OP--
As a licensed civil engineer (that means I am responsible for and can be sued if my seal is on the plan and somebody wants to sue over just about anything) it is my job to do horizontal and vertical alignments of roads (and rarely, railroads) for a living. There are many factual considerations beyond merely earthwork quantity balancing. What is the quality of the rock? Is it stable enough to tunnel through? Or will a tunnel bore require extensive lining and shoring? Today we do core borings to ascertain the condition of the material at the location of a proposed tunnel or structure of any kind. Additionally, if we build a fill, what must the slope be for stability? Where will the toe of fill slope be (we can't just dump rock in a watercourse as they did years ago)? We can't just re-align a stream as they did years ago--that's a no-no. And you need an Army Corps of Engineers' permit just to CLEAN an existing stream channel more than 50' upstream or downstream from an existing bridge (cleaning defined as removing deposits that have built up in the channel, that should not be there--it does not mean widening a channel at all).
So, for model railroad purposes, you are perfectly ok to build a tunnel if you desire and perfectly ok to have a steep cut if you desire.
Southern Pacific (now UP) still has numerous short length tunnels on the Tehachapi line--more than 20. Santa Fe (now BNSF) opted to daylight their tunnels on Cajon Pass. There are sound engineering reasons behind both decisions.
John
To give some idea of rock embankment slopes, the PA Turnpike now requires that all embankment slopes greater than 2 (horizontal) to 1 (vertical) must be rock armored (which is very expensive). So generally we stick to 2:1 or flatter steep embankment slopes.
In rock cuts, in very high quality rock, slopes can easily be steeper than 1 to 1, sometimes as much as 1/2 (horizontal) to 1 (vertical) or more.
If you notice, most existing railroad earthen fills seem to be in the range of 1.5 (horizontal) to 1 (vertical).
The Point of Rocks Tunnel was the original mainline for the railroad and rather than make it taller for larger equipment they bypassed it many years later and ran track around it. In the days they dug the original tunnel equipment consisted of men and hand tools. Even before blasting came in favor it was all hand labor. Removing all the rock and earth they removed later would have been much more costly and time consuming.
Often engineers would balance a cut with a fill and just transfer the materials. Very cost effective.
Roger Huber
Deer Creek Locomotive Works
Nittany:
There's a logical reason for the tunnel/sidecut arrangement at Point of Rocks. When the B&O was building west, the space between the rock cliff and the Potomac River was fully occupied by the C&O Canal, so the choice was to carve away the entire cliff face or tunnel through a portion of it. With the technology of the day, a tunnel would involve the removal of less material and would obviously be cheaper. So the line was built through the tunnel, which was eventually double tracked. In the mid-1920's, the C&O Canal was abandoned, with the property being taken over by B&O. As trains got larger, clearances in the old tunnel were too restrictive, so it was single tracked. B&O still needed the capacity of a double track railroad, so they built a new second track approximately on the alignment of the old canal towpath.
As Paul Harvey said, "So now you know the rest of the story."
Tom
Pittsburgh, PA
I see lots of tunnels on layouts that make me think "why would they have built it that way" or "how does that hill merit a tunnel." But then there's two examples I know if in the real world that challenge even my logic:
https://binged.it/2nxHKzi in Glenshaw PA outside Pittsburgh. Not a long tunnel. Not a tall hill. Apparently a cut works just as well as a tunnel because there's one of each a few dozen yards from each other.
The other is the Point of Rocks Tunnel, which is just perplexing to look at.
https://www.canaltrust.org/wp-content/uploads/2015/04/Point-of-Rocks-Train-Tunnel-Bruce-Saunders-1024x683.jpg
Yeah, that's a double tracked main. Yeah, one of the tracks is in a tunnel and the other isn't.
https://s-media-cache-ak0.pinimg.com/originals/97/90/f8/9790f83e1e8d981dff4ade036132924f.jpg
Bizz Johnson Trail Lassen County California
http://gordonsfotos.com/fotoblog/oct2006/bizzfall3.jpg
Blue Ghost Tunnel Grand Trunk Railroad
https://s-media-cache-ak0.pinimg.com/564x/b3/d6/ce/b3d6ce34a204a50a4a0c64528d8ed031.jpg
Tunnel Hill Illinois
https://s-media-cache-ak0.pinimg.com/564x/19/44/ee/1944ee658742b93861a65dcbbb2e3a22.jpg
Silver Cornet Trail Georgia
https://s-media-cache-ak0.pinimg.com/564x/27/e5/a9/27e5a9339228f3a09a84ae31777e54b3.jpg
Ashville North Carolina
https://s-media-cache-ak0.pinimg.com/564x/35/42/66/354266e841e35271ead42c5a02c56b43.jpg
Carrizo Gorge
https://s-media-cache-ak0.pinimg.com/236x/e8/52/ac/e852ac7953755cc487124e28e689c365.jpg
Caprock Canyon State Park
https://s-media-cache-ak0.pinimg.com/236x/1b/8d/9c/1b8d9ca2854423942e12f1dfb10c95a3.jpg
Hacketstown New Jersey
https://s-media-cache-ak0.pinimg.com/564x/8a/7a/63/8a7a633c054396cc1dddf216bf3ed5a2.jpg
Elephant Butte highway tunnel State Highway 70 Feather River Canyon California. Openings in side to admit light.
https://www.careypostcards.com/3013-thickbox_default/feather-river-highway-ca-grizzly-dome-tunnel.jpg
Clinton Massachusetts
http://freepages.history.rootsweb.ancestry.com/~howardlake/railroad/picture/cmass1.jpg
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
In real life 50 ft deep would almost always be a cut for modern construction. However in older days it might have gone either way. It's your railroad....
This is a cost/benefit thing, and the Civil engineers might decide on either option.
What is the composition of the ground? If it's loose, unstable material, a tunnel will need a lot of maintenance and will be prone to cave-ins. If it's solid rock, the tunnel will be more stable. Cuts always suffer from some erosion. If you use a cut through solid rock, the walls can be near vertical. If the ground is loose, the cut needs sloped walls, possibly as much as 45 degrees.
There are lots of other factors.
I'm currently constructing a long branch line. There is a section where it travels along a hillside and the plan calls for a large rock outcropping jutting out from the hillside which the line must pass through. It will be roughly 50 scale feet high and 120 scale feet to pass through it. Would a prototype railroad be more likely to bore a tunnel through such an obstacle or create a deep cut. My preference would be to go with a tunnel because it will be a more effective scenic divider but I want it to be prototypical as well. I've read stories about tunnels that got daylighted to a deep cut so I'm thinking either would be prototypical in this circumstance but I would like to confirm that.