Stockton Diamond

The Stockton Diamond is a railway junction in Stockton, California. It is the point where the north-south running Union Pacific Fresno Subdivision line crosses the east-west BNSF Stockton Subdivision, both double-track railways. Freight trains operate through the intersection 24 hours a day; Altamont Corridor Express and Amtrak California "San Joaquins" passenger trains also utilize the junction. Two of the sides of the "diamond" are complete and allow interchanges between the north-east and south-west legs.
Grade separation.
By 2020 the junction was the most congested in California, with the level-crossing design contributing to delays throughout the state's rail network. As part of the Valley Rail project, the San Joaquin Regional Rail Commission (SJRRC) and the California Department of Transportation (Caltrans) sought to grade separate the intersection to allow for future passenger rail expansion and reduce crossing interference. The Union Pacific line will be elevated above the BNSF line, with construction scheduled to start in 2023 and planned completion of May 2026.