These projects will help speed passenger and freight rail services by straightening the slowest, steepest, and highest curve territories of any segment on the LOSSAN corridor. Phase 1 of Sorrento to Miramar Double Track will provide 1.1 miles of second track, parallel to the existing track, south of Sorrento Valley Boulevard to east of I-805 in the Golden Triangle. A wooden trestle bridge built in the early 1940s also will be replaced, retaining walls will be added, and a new track crossover will be installed south of Sorrento Valley Boulevard.

The project’s second phase will add another 2.1 miles of double track and straighten the curves of the existing track as the rail line climbs toward Miramar Road. The current stretch of single track between Sorrento Valley and Miramar Road causes a significant bottleneck to rail traffic. Due to the sharp curves and steep grade, train speed there is restricted to 25 miles per hour. The planned work will substantially improve schedule reliability by increasing train speeds and allowing passenger and freight trains traveling in opposite directions to efficiently pass each other. More than 50 trains a day operate on the Sorrento Valley segment of the LOSSAN corridor.