The last two tunnels of the Middle Region of the Tunnel District are Tunnels 17 and 18. Tunnel 17 is the longest tunnel on the district, save the Moffat Tunnel at the summit. At 1730 feet in length, Tunnel 17 bores through a major ridge descending from Scar Top Mountain. To the West of this ridge lies Johnson Gulch, which drains a number of natural springs in the area. Due to the springs, water is often heard at the west portal of Tunnel 17.
To the east of Tunnel 17 was a spur named Quartz. The spur was removed by 1949, but up to that point, it was a source for some mineral shipments from the area. Should I decide to employ a little modelers license, I could include this spur at this location. At a minimum, I will need to allow for space for an abandoned spur in the area.
Tunnel 18 by contrast is a short tunnel with a length of 238 feet. It penetrates a shallow ridge coming off the northern side of Scar Top Mountain, and very easily could have been daylighted, but never has been. Tunnel 18 represents the western end of the Middle Region of the Tunnel District.
The space for the modeled representation of this area is physically located above the Cargill area just past North Yard. That part of the layout is at an elevation of 2.5" above the reference elevation while the mainline at west end of Tunnel 18 reaches 38" above the reference elevation. The elevation climb is an amazing accomplishment.
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| Track Plan for Tunnels 17-18 in relation to Tunnels 7, 8 and 10. |
Tunnel 17 helps achieve its length (83.2") by using the same trick of penetrating the the backdrop (previously used in Tunnels 8 and 10). However, in this case, the track of Tunnel 17 will be hidden in the mountainside above the track between Tunnels 8 and 10. At that point the elevation difference is about 5.5", so it should be easy to hide into the hillside. Tunnel 17 as modeled is a little shorter than Tunnel 10, but I may be able to address that discrepancy by moving the east portal of Tunnel 10 a few inches.
Beyond Tunnel 17, the hillsides become a bit more open and rolling as we approach Crescent Siding. Tunnel 18 is represented with a 16.5" long tunnel through the rolling ridge. Before leaving the garage, the main swings around to cross the doorway. With a mainline elevation of 38", I expect to be able to achieve a nod under crossing of the doorway with a lower edge of the benchwork at about 36" above the reference height. Since the reference elevation is likely to be around 30"-32", this places the nod under at about 66"-68", which should be fairly comfortable for many users.
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Days, 13 Posts to Go.
Cameron Turner
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