An $8-million steel-reinforced replacement bridge over San Mateo Creek at Trestles Beach in northern San Diego County opened last week as the northbound Amtrak Pacific Surfliner No. 769 train rumbled by.
San Diego Association of Governments (SANDAG), the project manager, says the design engineer on the project was HDR, Inc., and the joint venture general contractor was FLATIRON West/Herzog Contracting Corp.
North County Transit District purchased the tracks in the northwestern-most corner of San Diego County in 1992 from the Atchison Topeka and Santa Fe Railroad. The aging 858-ft wooden post-and-beam bridge – built in 1941 and officially known as the San Mateo Creek Bridge – required frequent and expensive maintenance to counteract the effects of age, fire damage, and corrosion, says a SANDAG spokesman.
Approximately 43 passenger and freight trains cross the bridge in a given day. Because of the condition of the trestles, SANDAG says the trains were required to cross slowly to reduce vibration and wear and tear.
The bridge is part of the LOSSAN corridor, which stretches 351 mi from San Luis Obispo, through Los Angeles and Orange County to downtown San Diego. Each year, more than 2.7 million intercity passengers and 4.5 million commuter rail passengers travel the LOSSAN corridor. Those numbers will be increasing as millions of dollars in LOSSAN corridor rail improvements – including extensive double-tracking – are completed in the years ahead.
The bridge replacement construction project – paid for with $8 million from the American Recovery and Reinvestment Act funds – began in fall 2010. The new bridge replaced the northern 558 ft of the wooden trestles. Workers built the steel reinforced concrete trestles right under the tracks and, once all were in place, shut down the tracks to rebuild the rail bed. The project was completed six months ahead of schedule and 5.5% under budget, says SANDAG.
The tracks are used by Amtrak and Metrolink trains and the freight haulers of the BNSF Railway.