The southwestern part of the Red Line runs on a private right-of-way with grade crossings.

At Lamar Street, the line turns north at a wye where a pair of tracks leading to one of two train yards on the system diverges.

The line terminates at the Parker Road Station at Park Boulevard near Central Expressway in Collin County.

The Red Line was part of the initial launch of DART's light rail testing and service in 1996.

Later that year, the line was opened to the Parker Road Station, an additional 3 miles (4.8 km) of track, its current terminus.

[1] The North Central Texas Council of Governments (NCTCOG) in a 2022 meeting discussed the possibility of expansion of the Red Line corridor from Plano through Allen to McKinney.