Project News
Field Note: Sorrento to Miramar Double Track, Phase One
![](https://www.flatironcorp.com/wp-content/uploads/2014/04/Sorrento-Double-Track-1.jpg)
The Sorrento to Miramar Double Track project in San Diego, Calif., is the first of two phases of construction to speed passenger and freight rail services on the Los Angeles-San Diego-San Luis Obispo rail corridor.
The project involves straightening part of the slowest, steepest, and highest-curve territory of any segment along the corridor. A wooden trestle bridge built in the early 1940s will also be replaced, and a new track crossover will be installed.
Flatiron proposed using innovative permanent soldier pile tieback walls on a portion of the project to owner SANDAG as a Value Engineering alternative to the conventional reinforced concrete walls, saving both time and money. The alternative wall design consisted of drilled-in soldier piles with temporary treated timber lagging between, and a permanent rock sculpted shotcrete architectural facing. Lateral support for the wall was provided by permanent tiebacks at taller wall heights. This wall system is traditionally constructed as a “cut” wall but was constructed successfully and economically as a “fill” wall in this instance.
Project completion is expected in April 2014.
![Sorrento Double Track (2)](http://flatironcon.wpengine.com/wp-content/uploads/2014/04/Sorrento-Double-Track-2-1024x681.jpg)
![Sorrento Double Track (3)](http://flatironcon.wpengine.com/wp-content/uploads/2014/04/Sorrento-Double-Track-3-1024x657.jpg)