Complex sentence: In October 1910, the GN began construction of a concrete snow shed to shelter the depot, it was then closed when the second Cascade Tunnel came into use in 1929, and the town was abandoned and burned.
Split into simpler sentences: In October 1910, the GN began construction of a concrete snow shed to shelter the depot. The depot was then closed when the second Cascade Tunnel came into use in 1929, and the town was abandoned and burned.