In 1883 the Denver and Rio Grande Western Railroad main line was built across eastern Utah. The rail line did not pass through Moab. Instead, it passed through the nearby towns of Thompson Springs and Cisco, to the north. Later, other places to cross the Colorado were constructed, such as Lee's Ferry, Navajo Bridge and Boulder Dam. These changes shifted the trade routes away from Moab. Moab farmers and merchants had to adapt from trading with passing travelers to shipping their goods to distant markets. Soon Moab's origins as one of the few natural crossings of the Colorado River were forgotten. Nevertheless, the U.S. military deemed the bridge over the Colorado River at Moab important enough to place it under guard as late as World War II.