Long Tunnels, especially straight ones

I thought I would share some thoughts on creating long tunnels. I know someone is working on the front range of the D&RGW, which will probably involve the MOffat at 6+ miles, and someone has also done the BNSF through Cascade Tunnel at 7+ miles.My own experience is (so far) limited to 7,854' at Sandy Ridge (VA).In this instance, I got my markers from the marker program posted last year to the file library, Convert31 I believe it is called. Often this does not produce completely accurate results, but in the case of the KP sub. it was right on.Creating the long summit tunnel was a matter of trial and error, but I found it was helpful if I placed the longest straight piece in the set at the correct elevation, and lined up as close as possible by eye to the line of markers. Unfortunately, the longest piece is pretty short. It would be nice if MSTS would produce 500M and perhaps 1000M pieces in any future release.After placing the longest piece, I then added pieces to it, until I reached the other end, and noted the offset. Then I went back and rotated the first piece slightly and repeated the process. It took 8 or 10 tries to get it within an acceptible error range, about 2 or 3 meters. Had I placed the piece within the center of the tunnel first, I might have improved on this.After getting the tunnel placed, I then connected the track (at Trammel Switch) to the tunnel with a short piece of Dynamic - which was not curved, rather I just needed to adjust the length. I had to adjust the last curve in the siding slightly to get perfect alignment.One of the more annoying aspects of Dynamic track is that you can get a seemingly perfect joint, no blue poles remaining, and still get a "bump" when you run the train. I have found that it is necessary to get in real close, and examine the joint(s) from all angles to be sure they really are good.The MSTS box, should carry this warning message"
1. Route editor may be addictive, recommend a twelve step process.
2. Before using route editor, supply self with a bucket of prozac.J. H. Sullivan, P.E. (retired)

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RE: Long Tunnels, especially straight ones, enocell, Sep-21-02, 03:22 PM, (1) RE: Long Tunnels, especially straight ones, redgar, Sep-22-02, 12:01 PM, (2) RE: Long Tunnels, especially straight ones, dwkarch, Sep-22-02, 02:35 PM, (3) RE: Long Tunnels, especially straight ones, landnrailroader, Sep-22-02, 04:49 PM, (4) RE: Long Tunnels, especially straight ones, Hoosac, Sep-23-02, 09:55 AM, (5) RE: Long Tunnels, especially straight ones, calr, Sep-23-02, 11:22 AM, (6) RE: Long Tunnels, especially straight ones, mivone, Sep-23-02, 11:45 AM, (7) Rollins Pass route? Great!!, markhyams, Sep-23-02, 10:35 PM, (8) RE: Rollins Pass route? Great!!, dwkarch, Sep-24-02, 05:46 PM, (10) RE: Rollins Pass route? Great!!, markhyams, Sep-24-02, 05:52 PM, (11) RE: Rollins Pass route? Great!!, dwkarch, Sep-24-02, 06:07 PM, (12) RE: Long Tunnels, especially straight ones, kenoman6, Sep-24-02, 02:20 AM, (9) RE: Long Tunnels, especially straight ones, LawrenceKellie, Sep-24-02, 07:37 PM, (13)

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>The MSTS box, should carry this warning message"
>1. Route editor may be addictive, recommend a twelve step
>process.
>2. Before using route editor, supply self with a bucket of
>prozac. Sometimes it comes to my mind that there should be warning like:
"do not use if you have weak heart"...
Some things RE makes "may" be "a little" annoying...
http://www.train-sim.com/dcforum/DCForumID6/6547.html
(the latest example)

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I know what you mean, I had the same issue with the 6,244 Hagans bore. After about 4 tries I finally gave up and put a curve in the blame thing. Now, if i hadn't told you, would you know there isn't sposed to be one in there? Adding to the fun of redoing it over and over the mountain it goes through (Cumberland) is a good 1300 feet above track level. I'm gettin dizzy, and can't see through the haze. I do envy you for your precise engineering data, but I still cling to the idea its' OK to be a little off to make the tracks look like they "fit" into the terrain. With the Hagans tunnel, the markers put me about 200 feet off on the Virginia side, but there's this depression demex created that looks for all the world like a cut leading into a railroad tunnel. So there's a curve under the mountain...

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I have done the Moffat tunnel, 6.21 miles. Longer tunnel pieces certainly would have been nice. One hundred pieces at 100 meters.I found on my DEMEX terrain the location of the east portal easy enough, although it sat about 12 meters too high and I failed to resolve that. What I did first was test the heading by using 500 meter non-tunnel pieces which is much quicker, and I first tried to set the heading simply by using the compass up on top, after review of the USGS hard copy quad. Not accurate enough for a 6 mile length, and I came out about 1200 meters too far south.Then I remembered how the first track piece heads straight north (don't know if that is true north or magnetic north or grid north), so I started with a 90 degree crossing below East Portal, put a dynamic track on the west side of it angled left .164 radians, and then jockeyed up to the portal location using short pieces of 4-track straights until I got north and west to the correct point. I started the tunnel from that spot (later deleting all of those previously mentioned track pieces for which I did not adjust terrain), and came out on the other side in approximately the correct location and with the correct tunnel length.I still had a bit of a problem with elevation when I used the actual 3 grades for the actual distances that occur in the actual tunnel, and did modify the grades to get to the right spot. Again, all tests were done with non-tunnel track pieces. Lot's of fun, and for my route the tunnel is just a diversion (double meaning intended), since my primary effort is building the old original route over the divide above the tunnel.

Don

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That is an intersting point, the way you got the East portal heading correct.On elevations in general, if you are working with railroad track charts, the grade may change many times in a few hundred feet if there is a variance in curvature. This is because the grade is "compensated" for curvature, i.e. more curve, less grade - but the resistance to the train is constant, more or less. Well we cannot do that very well in MSTS, so in figuring a grade, I took two known points, either elevations of tunnels, or points where a contour interval was crossed, and then took the AVERAGE grade between those points which I tried to not have further apart than 1/2 mile or so.
This produces the correct effect, but reduces the choppy result of trying to follow the charts too closely.J. H. Sullivan, P.E.

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I had a fairly easy time creating the 4.75 mile Hoosac Tunnel. You just need to know where to put the cross over the Mt.

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I know you can do this with scenery objects, not sure about track. Find a flat stretch of ground at least as long as your tunnel. Lay track straight for the required length. The direction doesn't matter at this point. Select all sections just laid. Pickup and move the entire group to the desired location and orient as required.
Cal Rasmussen
Beaverton, ORColumbia Gorge Route -- 20%
Old McDonalds -- Building done, Sign in progress.

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Sorry, that won't work: unfortunately, you can't select more than one track section at a time! Same for roads.BTW: I am writing a tool that will include the ability to "aim" track sections precisely between two distant points, and tell you exactly where to place them and how to orient them (by telling you the QDirection and Position for each track section, as they appear in the world tile files). One benefit for tunnels will be that you don't need to worry about the terrain shape over the tunnel (you will not have to change the terrain, even temporarily). This will be an add-on to the next edition of my Guide (which could be available in a month or so). Michael Vone
Step by Step Guide to Route Building for MSTS - http://trainsimulatorworld.com/catalog/b470.htm
Albula Line Route
Rocky Islands Route
Cliff Hanger Route
http://avsim.com/hangar/utils/mvchallenges/

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Don,Very clever way of figuring the correct angle for the Moffat Tunnel. I didn't know that you (or anyone) was working on the Rollins Pass line. Myself, I'm working on the Moffat line from Tabernash to Craig, and right now I have track laid from Tabernash to Toponas, some 88 miles. The longest tunnel I've had to deal with is Tunnel 52 in Egeria Canyon, which is 1325 feet long. Not that impressive. Here are some screenshots:http://www.train-sim.com/dcforum/DCForumID6/6381.htmlI was actually considering working on the Rollins Pass line myself, as a friend of mine came across an engineering profile chart that shows the curves, spirals, elevations, bridges, snowsheds, and tangent directions (down to the nearest minute). It's on an extremely long roll of paper drawn at a scale of 2.5 inches = 1000 feet. But now that you're doing the Hill line, it will free up my mind to concentrate on finishing my line all the way to Craig.Unless you really feel like it, you can stop your track at Tabernash, since I've already laid track from there to Granby. It is pretty fun to lay track through the Fraser Canyon, however. Can't wait to see all those 16-degree loops on the Hill line. I'd love to see some screenshots of what you've done!MarkMoffat Road Tabernash to Craig (52% of track laid)

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Well, I haven't done much. Just 5 miles or so besides the tunnel so far. Most of that is below the tunnel, but am now ready to continue up the hill route. You did, however, get me to learm how to get screen shots, and in the necessary format. So here are shots of some of the little bit I've done so far, assuming I can get this to work!!!!I've seem some of your screen shots and look forward to your route! Hopefully you'll get some water in the Colorado River. It's been so dry here, but not THAT dry. (Joke)

Don

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http://www.train-sim.com/dcforum/User_files/3d90dbf774284003.jpg

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Nice shots. Can tell where you are exactly. Looking forward to it. Have you run a train through Moffat Tunnel yet? Is it cool?Mark

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Mark,John CS (I believe that's right) will appreciate your testimonial with regard to DEMEX!!!Yes, I have driven a speedster through the tunnel, and it is really neat. Can get boring, but at 80 MPH it's not too bad!! Also tried the Big Boy, but with nothing to see but the cab, I hit the escape key. I'm kind of glad that most steamers have a "windshield" with a good view.

Don

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My god! Some one is doing Rollins Pass!
Thank you! Thank you!I have been buying postcards of Rollins Pass on E-bay.
Many are "colorized" ( b/w photo that is hand tinted before printing, or something like that ).
If you need scans of them for textures, let me know.You may know of this site already:http://terraserver.homeadvisor.msn.com/image.aspx?t=1&s=11&x=1098&y=11041&z=13&w=1click on the "view" above the compass rose on the left.Kenoman6
Las Vegas, NV

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I have found creating precise straight tunnels very easy. I created an Excel spreadsheet, where I can determine the values of the initial angle for the first track to 7 or 8 decimal places. By laying a 500m straight, then continuing it for some length--7 to 8 km--I can get the the angle precisely following the markers that I created from satellite photos. So, you say, how can you see the track? I click the Y key, of course! Well, doesn't that leave a trench, when you should be going *through* the hill? Yes, but that leads to the second technique. However, to finish the first, after finally getting the angle to the 7th or 8th decimal position, I then attach a tunnel piece to it and work backwards with tunnel pieces.So after laying all the tunnel track, I just run the tiles through Dem-ex again! Viola. Perfect tunnel, perfectly positioned, perfectly underground.Laid the Cascade tunnel with precision and ease. Lawrence

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