Photo: National Park Service, Golden Spike National Historic Site (Some rights reserved)
Second Saturday in May in the USA
Wikipedia: National Train Day was a holiday started by Amtrak in 2008 as a method to spread information to the general public about the advantages of railway travel and the history of trains in the United States. It was held each year on the Saturday closest to May 10, the anniversary of the pounding of the Golden spike in Promontory, Utah, which marked the completion of the first transcontinental railroad in the U.S. Events were held at major Amtrak stations as well as railroad museums across the country and often have passenger cars and model railroad layouts on display. The largest events took place in Washington, D.C., Philadelphia, Chicago and Los Angeles. National Train Day was cancelled after 2015 due to budget cuts within Amtrak, although other rail organizations continue to observe the holiday.