Union Depot was built by the Northern Pacific about 1911 or so. MP 54 is about even with the station agent's rectangular bay window at the middle of the station. Only a few decades ago, there was a pair of semaphore signals connected to the station wall, controlled by the station agent.
While the only passenger trains this station currently serves are 3 or 4 Cascades trains and the Coast Starlight in each direction each day, it once hosted well over a dozen trains from Northern Pacific, Great Northern and Union Pacific. Through trains ran between Portland, Ore and Tacoma and Seattle, WA. This station also originated and terminated trains to the coast at Raymond/South Bend, WA as well as a connection to the Tacoma to Hoquiam train at Gate, WA.