Tunnels 24, 25, 26 and 27

Beyond Tunnel 23, the main line continues to climb. With each successive tunnel, the track gets closer to the banks of South Boulder Creek, which finally arrives trackside just after the west portal of Tunnel 26.

Tunnel 24 is a bit more separated from Tunnel 23 than was the norm to the east of Tunnel 23. The approach to the east portal of Tunnel 24 is a fill over a deep chasm which was likely spanned by a trestle at some point. Tunnel 24 penetrates a rocky ridge with a bore 815 feet long. To the west of Tunnel 24, two rock cuts are used to penetrate smaller rock ridges.

DRGW5385 leads four sister units eastbound out of Tunnel 24 with a coal train off the Craig Branch. Cut into the train are two more units 70 cars back serving as a swing helper. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

Tunnel 25 cuts through another rocky ridge with a 643 foot bore. The proximity of South Boulder Creek is increasingly evident in the location and curvature of the tracks and the increasingly rough terrain that it replacing the weathered and rounded features present around Crescent.

Amtrak341 leads the westbound California Zephyr out of Tunnel 25. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

The 295 foot length of Tunnel 26 penetrates another rocky spur extending into the canyon. To the west, is an active landslide zone, and some evidence of previous derailments, such as one that occurred in September 1991.

The rough terrain to the west of Tunnel 27 shows the dramatic changes to the landscape as the banks of South Boulder Creek approaches track in the narrowing canyon. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

As we approach Tunnel 27, having finally reached the inner gorge of South Boulder Creek, the creek quickly turns away from the track into a tight horseshoe bend that the railroad could not hope to follow. So, Tunnel 27 was used to bore through the ridge of the horseshoe. The resulting tunnel is 646 feet long. To the west, the mainline emerges on a shelf blasted into the canyon wall, that includes retaining walls that use lengths of rail in their construction.

DRGW3129, DRGW3040, DRGW5334 and DRGW5337 heads west out of Tunnel 27 through the inner gorge of South Boulder Creek Canyon. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

SP357 westbound out of Tunnel 27 from the banks of South Boulder Creek. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

These are dramatic and compelling scenes to model. When the elevation of these scenes, (approximately 6 feet) is considered, the view of the trains will be similar to the image above for most people.

Track plan for Tunnels 24 through 27 in South Boulder Creek Canyon.

The plan for the representation of these tunnels uses the upper wall of the garage located above the locations of Rocky siding and LDEs such as Blue Mountain Crossing and Coal Creek Canyon. The tunnels are again in proportion, with Tunnel 24 at 45.1", Tunnel 25 at 37.4", Tunnel 26 at 19.9" and Tunnel 27 at 37.7" in length. One minor modification I may make is to bring South Boulder Creek into view between Tunnel 26 and Tunnel 27. I have looked at the satellite photos of the area, and the distance to the riverbank from the track would place the river in the aisle, but I may include the edges of South Boulder Creek anyways. During this run, the grade resumes, and the mainline will climb from 40.5" to 43.875" when exiting the west portal of Tunnel 27, forming a grade of 0.83%. This is less than the actual grade, but sufficient to gain about 18" of railhead to railhead elevation over Plain siding. So, at this point, while I would like to maintain a climbing grade, I no longer need to have as much of a grade as was necessary on the second deck. Furthermore, too much grade would result in the mainline reaching the ceiling of the the garage. One additional advantage of this height though is that the mountainsides will rise well above eye level, which should make forced perspectives to increase the apparent height of the mountainsides even more effective and realistic.

8 Days, 8 Posts to Go.

Cameron Turner