Altoona Pennsylvania is home to Lakemont Park. It has been known as various names over the years, but it is one of the oldest amusement parks in the United States constructed in 1894. It is also home to the oldest roller coaster in the world. The roller coaster is called Leap-the-Dips and was built in 1902 and is the oldest wooden roller coaster of it's type.
At one point in the roller coaster's history, a maintenance worker was working on one of the tracks when he was struck and killed by the coaster during a test run.
Over the years there have been stories of folks riding the roller coaster and spotting a man working on the tracks during their ride. When the ride ends and they report the close proximity of the man on the tracks, making sure the ride operator knew the worker was there, they learn that there was no maintenance worker working on the coaster at that time. What they have seen is the ghost of the dead maintenance man killed long ago.