Mountain Quarries Railroad Bridge

Leonard argued that concrete gains strength as it ages, and the river has been testing him since 1912. When the Hell Hole dam failed in December 1964 the flood took out two newer bridges upstream; this one stayed on its footings and carried the traffic between two counties for the hundred and seven days it took to rebuild Highway 49. The Valentine's Day flood of 1986 submerged it and it held. Three men died when the third arch came down during construction in November 1911.

What the plaque says

Mountain Quarries Railroad Bridge This bridge, built to carry limestone from nearby quarries to the city of Auburn, was a very early use of reinforced concrete in railroad bridge construction and the largest such railroad bridge in California at the time it was built in 1912. The bridge was designed by John B. Leonard, who became one of California's most renowned pioneers in the design, engineering, and promotion of the use of reinforced concrete. State Registered Historical Landmark No. 1051 Registered February 7, 2014 Plaque placed by California State Parks in conjunction with Placer County Historical Foundation Dedicated 2014, the 150th anniversary of California State Parks

Where it stands

Worth the stop nearby

• Marshall Gold Discovery State Historic Park — 12 mi
  The tailrace at Coloma where a carpenter found gold in January 1848 and the world came running.
• Empire Mine State Historic Park — 20 mi
  The oldest, deepest, richest hard-rock gold mine in California, with 367 miles of flooded tunnels underneath.
• Nevada City — 24 mi
  Gaslamps, brick storefronts, and the Nisenan who are still fighting to be recognized on their own ground.

More markers nearby

• Site of California's First Grange Hall — 5.0 mi
• Greenwood — 6.9 mi
• Overland Emigrant Trail — 11 mi
• Georgetown — 11 mi