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"Hack of Wimpy Three-Degree Grade Limit Unsuccessful"

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WaltN (13 posts)
Aug-10-01, 12:39 PM (EST) "Hack of Wimpy Three-Degree Grade Limit Unsuccessful" I'm modeling the 1827-1933 Mauch Chunk & Summit Hill Railway (popularly known as the Switch Back). (See www.switchbackgravityrr.org for prototype information. If that link is down, as it has been frequently this summer, sample home.stny.rr.com/wniehoff/sbgrr.htm for my N-scale attempt.) The most interesting features of this railroad were two inclined planes, put into operation in 1845, one at 16.6 degrees and the other at 12.9.The three-degree grade limit has been mentioned more than once in this forum, but, since I hadn't run across it in any of the product-related documentation, I had to see for myself. I performed the following experiment: I constructed two 500-meter straights arranged side-by-side and elevated at the three-degree max permitted by the Properties dialog. Exiting from Route Editor, I edited the pertinent .w file using WordPad, a suggestion found in the forum from John Stanford related to getting better precision in grade specification. Finding the only two A2t500mstrt sections in the file (the ones I had just added), I verified that they both showed Elevation set at -0.0523598 (radians), which is -3 degrees. I modified one of them to double that, or -0.1047196. Back into Route Editor, and there sat the two straight sections at exactly the same visual slope. I did another experiment where I manually edited the .w file to give me the 16.6 degrees I need for one of my planes. Same experience. Interestly, however, although the visual grade was 3 degrees, a properties query showed the desired grades in degrees.Disappointed, but still curious, I went back to WordPad and the .w file. I left the -0.0523598 elevation alone but modified the other one to -.01, that is, reducing the slope to something within spec and a difference that should be noticeable. Back into Route Edit and there they sit, both at 3 degrees. Go figure!Now disappointed and mystified, I suspect there is a redundant specification somewhere of the grade angle. The only other file I noticed that was changed was the .tdb file, but, on inspection, I see no buttons to push.Am I missing something? Any suggestions?I've made progress modeling a couple of miles of the 1827 Down Track (gravity down, mules back). The Route Editor, with all its warts, can be gotten used to -- even dynamic track with right-hand curves.Developers note:

The apparent three-degree grade limit effectively prevents modeling the most interesting feature of many historic railways that included inclined planes (e.g., the D&H, the Portage). American and European funicular railway fans will be disappointed as well.The no-loop topology limit also hits me: The Switch Back was a twice-twisted closed loop: Eastbound traffic, gravity only, on the Down Track and Westbound traffic, gravity plus two inclined plane assists on the Back Track.
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Subject Author Message Date ID RE: Hack of Wimpy Three-Degree Grad... john Aug-10-01 1 RE: Hack of Wimpy Three-Degree Grad... WaltN Aug-10-01 2 RE: Hack of Wimpy Three-Degree Grad... WaltN Aug-11-01 3 RE: Hack of Wimpy Three-Degree Grad... jkcooney Aug-21-01 4 RE: Hack of Wimpy Three-Degree Grad... WaltN Aug-21-01 5

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john (135 posts)
Aug-10-01, 02:04 PM (EST) 1. "RE: Hack of Wimpy Three-Degree Grade Limit Unsuccessful" Have u ever been to the Allegheny Portage Railroad museum? Just to say, the have an acurret full-size replica of the lemon house, engine barn at the crest of the hill, and about one hundred feet of replicated trackage, not to mention the main museum with original track, a steam loco replica and a model of the plane Remove | Alert Edit | Reply | Reply With Quote | Top
WaltN (13 posts)
Aug-10-01, 04:17 PM (EST) 2. "RE: Hack of Wimpy Three-Degree Grade Limit Unsuccessful" Yup. What I liked best there was the full-scale model of the stationary steam engine, transmissions, etc. Remove | Alert Edit | Reply | Reply With Quote | Top
WaltN (13 posts)
Aug-11-01, 09:30 AM (EST) 3. "RE: Hack of Wimpy Three-Degree Grade Limit Unsuccessful" Now that I've figured out how to get images in these posts, I thought I'd add some. This first one is the prototype Mt. Pisgah Plane -- 28.6% grade (16.6 degrees).

The following are two screen shots from yesterdays maiden trip on the first couple of miles of the route. The first shot is the approach (gravity-powered) to the eastern (Mauch Chunk goes in the valley below) terminus. (The CNJ and LVRR ran in the slot on the right in the distance.)

Return trip (diesel-powered). I'm using the KIHA 31 as the closest current approximation to a prototype car.
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jkcooney (386 posts)
Aug-21-01, 08:06 AM (EST) 4. "RE: Hack of Wimpy Three-Degree Grade Limit Unsuccessful" I'm having trouble getting SMOOTH transitions from my flat track to an ascending grade. Any suggestions? I will be nowhere near what you want for your inclined plane route but I will be approaching 2.5%!
Help if you can. Those kinks in the track (sharp up and down pitches} are annoying. There mus t be a way to avoid them.
Joe Cooney Remove | Alert Edit | Reply | Reply With Quote | Top
WaltN (13 posts)
Aug-21-01, 01:59 PM (EST) 5. "RE: Hack of Wimpy Three-Degree Grade Limit Unsuccessful" Unfortunately, there are no vertical curves, so we have to approximate piecewise. I've got some cases where my Down Track grade varies between 0 and 1.5 percent over a mile or so. What I did was fudge in gradual changes with relatively short pieces of track, of course, holding down the End key to get finer control over the rotation. Yesterday, I ran my first piece of dirt road and was astounded to find that the 3 degree limit did not apply with road. I had hoped that there was some technical reason why Kuju set the 3 degree limit. Now I doubt that there was???? Remove | Alert Edit | Reply | Reply With Quote | Top

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