Durango & Silverton Railroad Locomotive on Bridge Card

"Durango & Silverton Railroad Locomotive on a Bridge over the Animas River in Colorado" by Catherine Sherman A train locomotive on the Durango & Silverton Narrow Gauge Railroad (D&SNG) conducts a "blowdown" on a bridge of the Animas River, in Colorado, in which the lengineers blow out mineral sediments in the boiler water. The addition of various chemicals in the tender water is designed to keep the sediments from sticking to the internal steel components of the firebox/boiler. These "settled" sediments regularly need to blown out at safe locations on the railroad. The Durango & Silverton Narrow Gauge Railroad is a 3 ft (914 mm) narrow gauge heritage railroad that operates 45.2 miles (72.7 km) of track between Durango and Silverton, in the U.S. state of Colorado. The railway is a federally designated National Historic Landmark and is also designated by the American Society of Civil Engineers as a Historic Civil Engineering Landmark. This historic train has been in continuous operation between Durango and Silverton since 1882, carrying passengers behind vintage steam locomotives and rolling stock indigenous to the line. The line was constructed to haul silver and gold ore from Southwest Colorado's San Juan Mountains, but passengers soon realized the view was even more valuable. The railroad runs 45 miles (72 km) from the Durango yard to Silverton, crossing the Animas River five times throughout the trip. Once trains reach Silverton and unload passengers, the train is turned on the wye, backs uptown to pick up returning passengers, and makes the trip back to Durango. One way scheduled trains take 3½ hours to run the 45 miles (72 km) each way, with a 2¼ hour layover in Silverton. A narrow-gauge railway (narrow-gauge railroad in the US) is a railway with a track gauge narrower than standard 1,435 mm (4 ft 8 1⁄2 in). Most narrow-gauge railways are between 600 mm (1 ft 11 5⁄8 in) and 1,067 mm (3 ft 6 in). Since narrow-gauge railways are usually built with tighter curves, smaller structure gauges, and lighter rails, they can be less costly to build, equip, and operate than standard- or broad-gauge railways (particularly in mountainous or difficult terrain).