This is the former Union Pacific Railroad Depot in Greeley, Colorado. The depot was built in 1930. While the Union Pacific still runs behind the depot, it's now the Greeley Convention & Visitors Bureau.
Deep under the streets of London and its snarl of urban traffic is a virtually unknown railway that for 75 years was an artery in Britain’s postal network. Seventy feet below ground, the Post Office railway (more commonly known as the Mail Rail), carried post from Paddington to London sorting offices from 1923 until it was finally abandoned in 2003 due to changing technology.