Mind the Gap: The Legend of the Silverpilen

Wiki:

Silverpilen ("The Silver Arrow") is a ghost subway train that haunts the Stockholm Metro, according to an urban legend circulating in the Swedish capital Stockholm. The train is usually referred to as being composed of silver model C5 cars. Only one such train, composed of eight cars, was built; it was manufactured in the mid-1960s as a test and taken out of service years ago and replaced by more modern cars.

The silver train was rarely seen, which may have given rise to stories of a mystical white, shimmering ghost train, especially if people saw it at night. The stories that circulated most widely in the 1980s have been retold by the noted Swedish folklorist Bengt af Klintberg, and later featured in an installment of a television series dedicated to allegedly real ghost stories and haunted houses, Det spökar, aired on December 10, 1997.

There are different versions of this urban legend. Some say that the ghost train has only been seen in abandoned tunnels by subway workers. Others say that anyone can see it passing the stations at high speed after midnight. Some even claim that Silverpilen sometimes stops to pick up passengers, who then disappear forever or later "get off" weeks, months or even years after they embarked. The inside of the train is described as being empty, or as containing one or several ghost passengers.

Some stories connect the ghost train with the abandoned Kymlinge metro station on Line 11, the blue line. Kymlinge also has a reputation of being a ghost station, with people saying that "Bara de döda stiger av i Kymlinge" -- "Only the dead get off at Kymlinge." The ghost stories of Silverpilen can be compared to those of the ghost ship The Flying Dutchman.