Starting north from Shrewsbury, the alignment crosses BNSF's Southeastern Junction and follows former Terminal Railroad Association of St. Louis right of way to Clayton, briefly along Interstate 170.

[4][5]In 1999, East-West Gateway staff members submitted an updated conceptual design for Segment 1 of the Cross County extension between Forest Park and Shrewsbury.

[8] Citing repeated delays and cost overruns, Metro fired and then sued its general contractor, Cross County Collaborative, in the summer of 2004.

[12] On July 26, 2022, portions of the Blue Line were impacted by a flash flood that shut down the system for nearly 72 hours and caused roughly $40 million in damage.

[citation needed] It then proceeds north in a tunnel underneath Interstate 64, continuing to the Richmond Heights station serving the popular Saint Louis Galleria shopping mall.

[citation needed] After crossing the St. Louis City/County boundary, the Blue Line makes its last stop at the Skinker subway station serving nearby Washington University.

[citation needed] From Shrewsbury−Lansdowne I-44 to Fairview Heights (west to east) In 2002, Metro's Arts in Transit program commissioned a group of artists to join architects and engineers during the design phase of the Cross County extension.

[25] The work of these artists involved exploration of landscape alternatives, designing the paving patterns for concrete adjacent to stations, and creating the “flow”-patterned retaining walls running along the tracks in the below-grade stretches of the alignment.

An overlay of lacy aluminum silhouettes, titled A Walk in the Park, embellishes the concrete privacy fence, called the Catlin Wall, which runs parallel to the tracks between the Skinker and Forest Park-DeBaliviere stations.

Created by Andy Cross, Carl Harris, and Ty de LaVenta, the work is a series of cut metal panels depicting trees, vines, leaves, and trellises.