The Pecos River, a major tributary of the Rio Grande, long hindered transportation across the deep gorge near its junction with the Rio Grande. The first railroad bridge over the Pecos was built in 1882 as part of the Southern Pacific Railroad’s transcontinental route across the lower United States, reached by a circuitous route and two tunnels because it lay deep in the canyon. In 1890, Southern Pacific officials began planning a new bridge that would cross the ravine directly with a high-line viaduct, saving miles and straightening the route. Work began in late 1891 and was finished within three months at a cost of more than $250,000. Supported by 24 towers, it was the highest bridge in North America and the third highest in the world when completed. Passenger trains slowed to six miles per hour before crossing and stopped on the bridge so travelers could take in the view. During World War II, the Pecos High Bridge became essential for moving war materials. As trains grew heavier and wartime demand increased, a new bridge was built in 1944 with special permission from the War Production Board to use critical materials. That 1944 Pecos High Bridge remains in use, though the gorge is no longer as deep as it once was because construction of Amistad Reservoir raised the river.