DENVER (CBS4)– Part of RTD’s new commuter line to Denver International Airport is on display at Union Station.

The commuter rail cars on display will be used on the East Line.

The cars were assembled in Philadelphia and shipped four at a time by freight.

(credit: RTD)

(credit: RTD)

The rail cars will be used on four FasTracks lines in 2016, the East Rail Line to Denver International Airport, the Northwest Rail Line to Westminster, the Gold Line to Arvada and Wheat Ridge, and the North Metro Rail Line to Thornton.

Commuter rail trains are heavier and travel faster than light rail vehicles but operate in a similar way using overhead electric lines. The trains will travel up to 79 miles an hour. Commuter rail is used on longer lines and make fewer stops than a typical light rail system.