ROANOKE, Va. -

A special steam freight is set to return to Roanoke. The Class Y6a 2156 steam freight locomotive is coming in from Missouri to be reunited with the rest of the "Big Three" locomotives.

The steam freight locomotive was designed and built in Roanoke and is the only survivor of the of N&W’s Y-Class.

“We are so pleased that Norfolk Southern helped facilitate the discussions between us and the Museum of Transportation. They have helped us bring another one of Roanoke’s finest accomplishments back home,” said Beverly T. Fitzpatrick, Jr., executive director of the Virginia Museum of Transportation.

The Class Y6a is one of the most powerful and advanced steam locomotives. They were used for slower, heavy freight trains in the more mountainous districts.

The Class Y6a 2156 was built in March 1942, retired in March 1959 and donated to the Museum of Transportation in St. Louis, Missouri, in July 1959.

In exchange, the Virginia Museum of Transportation is sending one of its own historic locomotives to St. Louis.

The Virginia Museum of Transportation doesn't know yet when the trains will be swapped.