Aspen's boom years ended in 1893, when Congress repealed the Sherman Silver Purchase Act in response to that year's economic crisis. With the market no longer artificially supported, the price of silver dropped and many of the city's mines closed, beginning a long period of the city's history known as "the quiet years". The railroad, which had recently built the Busk–Ivanhoe Tunnel, which improved service along its main line, continued operating even as it went bankrupt in 1897, and reemerged as a new company with the same name. The second Colorado Midland went bankrupt again in 1919, as most of Aspen's remaining silver mines shut down. The bridge remained, unused.