The Durango & Silverton Narrow Gauge Railroad is a remnant of the Denver & Rio Grande Western's 3 ft. narrow gauge empire of the 1880s in Colorado. This once extended all the way from Denver, via Pueblo, Walsenburg, LaVeta Pass, and Alamosa, all in Colorado. By the mid 1930s, this line had been standard-gauged all the way to Alamosa, with dual gauge track between Alamosa and Antonito. The line from Antonito to Durango, and the branches thence to Silverton and Farmington, remained narrow gauge to the end of its days in daily freight and passenger service. After closure of the line, in 1968, the 45-mile Silverton branch remained open for tourist trains. In the 1980s, D&RGW sold the Silverton branch to the D&SNGRR, who have rebuilt and replicated the stock, and added service, to cater to the tourist trade.
The depot in Durango (MP 451.5, from Denver via Walsenburg and Chama, el. 6,520 ft.), which has a two-level central section and two single-level out sections, is on the east side of the line at the southernmost point of remaining original right-of-way, where the tourist line has a clockwise balloon track around to the west side of the replacement roundhouse (following a fire in the 1980s), and then north-northeast to rejoin the main line as it turns north-northeast out of the depot past the signal tower and across College Drive (with a McDonald's alongside to the west). Trains from the yard pull north of the depot and then back in. Returning trains, headed south, pull around the balloon track to turn after making their station call. From Durango, the line heads north-northeast, with a highway alongside to the west, over city street crossings at grade (College Drive, 7th, 8th, 9th, 11th and 12th Streets, the intersection of 14th & Main as the line turns northeast, and the intersection of 15th Street and East 2nd Avenue), then out into the countryside, past the former location of a track east across the valley to City Mine, crossing the Animas River on a through truss bridge while heading northeast, before turning north-northeast again
The line follows the west bank of that river, with town still on the west side in 2006 that was not there in 1994, past a pedestrian crossing leading to a footbridge across the river to the east, a street alongside to the west, Animas City, a grade crossing with a street that bridges over the river, Ireland, where it turns north, a dirt road grade crossing, new housing (in 2006) alongside to the west, a dirt road grade crossing, construction (in 2006) alongside to the east, housing construction (in 2006) alongside to the west, and then the highway alongside to the west (for the enxt several miles), a dirt road grade crossing to a "ranch" on the east side, two dirt road grade crossings to farms on the east side, the 700 ft. siding at Home Ranch (MP 457.3), a dirt road grade crossing to housing on the east side, MP 460, a dirt road grade crossing, a golf course on the east side, a grade crossing at Trimble, MP 461, a grade crossing, manufactured housing on the east side, a grade crossing, MP 462, a dirt road grade crossing, and a through truss bridge over Hermosa Creek.
There are red mountains on both sides of the Hermosa Valley. The line turns north-northeast past the 600 ft. siding at Hermosa (MP 462.5, el. 6,645 ft.), where there is a water tank on the west side of the line, and a grade crossing where the highway (US 550) crosses to the east side, and MP 463. A 2.5% grade starts, taking the line onto a ledge on the west side of the valley as it turns northeast, past two grade crossings to ranches on the west side, Honeyville (not a railroad location), MP 464, a dirt road grade crossing, and houses on the east side, and then north again, past the valley below to the east with the line up on a ledge with sheer hills to the west, MP 465, Pinkerton (MP 465.8) and Bell, a 10 mph speed restriction, and the highway alongside to the east now at the same level as the line, which turns east-northeast, and is then on a ledge with the highway again well below to the east.
Almost without warning, the line enters onto a meadow, as the rock wall falls away to the west (MP 468), the highway crosses at grade, and the line climbs from the meadow into woods, with a lake/pond below to the east and a rock wall to the west, and then enters an open area with the housing of Rockwood on the north side as the line turns east to the 1,200 ft. siding on the east side at Rockwood (MP 469.1, el. 7,367 ft.), where there is a wye, a dirt road grade crossing within the siding, and maintenance-of-way equipment stored on a spur. The highway heads away north, using a different valley from that which the railroad uses, almost all the way from Rockwood to Silverton. The grade from Hermosa to Rockwood is 2.5% all the way..
Just past Rockwood, the line passes through a deep and narrow rock cut, turns north and emerges onto a narrow ledge, curving back and forth several times, 400 ft. above the Animas River (one of which is at an elevation of 7,200 ft.), and a similar amount below the top of the cliffs, with the track descending on a 1.42% grade. The cliff sides are heavily wooded with firs and pines. This area, traversed at restricted speed (well below the line's normal 15 mph maximum), is known as the “High Line”. Continuing north, past MP 471, the line crosses the river on a high, 130 ft. long, deck truss bridge, and then turns alongside the river on its east side. Not much further north, in an area where the river has whitewater rapids, the tracks and river are at the same level again.
The line continues past MP 472, a bridge over a side stream to the east, a power house on the west side, on the river at the south end of the 900 ft. siding on the east side at Tacoma (MP 472.3, el. 7,313 ft.), where a 2.5% upgrade starts again. The line now runs along the east side of the river in a narrow valley, curving back and forth to follow the river, past Ah Wilderness Ranch (MP 474.0, el. 7,473 ft.), where a broad meadow appears on the east side, followed by a stretch with whitewater river to the west and rock walls to the east, Tank Creek (another water tank), another meadow on the east side, north of the tank, Tall Timber (MP 475.3), with a ranch style house on the east side, and a bridge over a cascading stream on the hillside to the east, and the line runs on a ledge above the east side of the river, where there are more whitewater rapids.
At Cascade Wye (in Cascade Canyon, MP 477.6, el. 7,595 ft.), the line turns east and crosses the river again to run on its north bank at river level, past Tefft (MP 478.0, el. 7,712 ft.), heading northeast for a while past the Cascade Siding signpost (MP 478.4) more white water very near track level, MP 481, and then climbing a little above the river, slowing to 10 mph for a river bridge above white water, past MP 482 and MP 483, a footbridge over the river, more whitewater at track level at the south end of the 600 ft. siding at Needleton (MP 484.0, el. 8,293 ft.), where there is another footbridge over the river, and heading north-northeast past MP 485 and Needleton Tank (with yet another water tank, on the west side). There are the remains of a large rock slide (Garfield Slide) on the east side. In June, the river level is high enough to run in areas that otherwise would be footpaths, etc. There is a bridge over a side stream (Tenmile Creek) on the north side of the line, MP 487, the start of lodgepole pines replacing the former mix of firs and (other) pines on the north side, and MP 489
The line heads northeast, across a bridge over a cascade on the west side, with a very low speed restriction, and then north, past a steep mountainside stream on the east side, across a deck bridge over the river just downstream of an old through truss bridge also across the river, past MP 490, through the 700 ft. siding on the east side at Elk Park (MP 490.5, el. 8,883 ft.), where there is a wye on the east side, and King Mine, through an area with several slides along the canyon walls, past MP 491, a pond on the east side, a slide area on the east side, the river almost at track level on the west side and a steep hillside on the east side, a bridge over a gurgling side stream on the east side, and a small bridge over a side stream on the east side. The line curves back and forth following the east bank of the river, past slide areas to the east and across the river to the west in a narrow valley with a stream, a former coaling tower on the east side at Kendall Creek, MP 495, the Detroit Mine up on the hillside to the west, and then across the river again on a deck bridge, with the river then alongside to the east at track level, past Ross and Hercules,
The line turns north-northeast where a spur to the erstwhile Silverton Smelter once headed west, passes the Yard limit sign, another wye (where a line once headed to mines in the mountains to the northwest), now used for turning the trains, and another water tank, with a number of sidings on the northwest side including many decaying old freight cars and 2-8-2 493, cold and dead, and the old (but still in use) depot on the north side of the line, and reaches Silverton (MP 496.7, el. 9,288 ft.), where trains turn northwest to park on 12th Street adjacent to the main street (Blair Street) for the lunch stop. Trains back out, use the wye to turn, and back in again, before reboarding after lunch. Lines once continued northeast beyond 12th Street to mines in the mountains to the north and northeast.