Denver and Rio Grande Western steam charter with locomotives 476 and mid-train helper 473 pull a freight and passenger train through Horseshoe Curve during our two-day charter between Durango and Silverton, Colorado on October 17th, 2023. The lead locomotive had just finished a blowdown, resulting in a rainbow in the steam cloud.
A blowdown is a way to get minerals and other contaminants out of the system. Engines want to be on a bridge or trestle because the blow down itself can reach 30+ feet at an angle away from the firebox with live steam.
According to Wikipedia: The Durango and Silverton Narrow Gauge Railroad, often abbreviated as the D&SNG, is a 3 ft (914 mm) narrow-gauge heritage railroad that operates on 45.2 mi (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 was also designated by the American Society of Civil Engineers as a National Historic Civil Engineering Landmark in 1968.
Tech Info: DJI Mavic 3 Classic Drone, RAW, 22mm, f/2.8, 1/1000, ISO 500.