Starting in the 1860s, the people of the Sonoma Valley became interested in their own railroad connection. During 1874 the discussion and want for a railroad had become intense. Joseph S. Kohn came forward to incorporate the Sonoma Valley Prismoidal Railroad using the "Crew Prismoidal One-Rail System" (kind of like an old verison of a monorail!). The Prismoidal Railroad was laid upon a prism of wood built of beveled boards, forming a continuous prism 27 inches wide at the base and 15 inches high, with the single rail laid on top. The car which traveled on the line was supported by two wheels, one at the front and one at the rear, with independent revolving flanges.
Proposed to connect Sonoma with deep water at or near San Pablo Bay, a distance of 7 miles, surveys for the line began on February 17th, 1875. Grading began during June 1876 with construction of 3 and one half miles of grade north from Norfolk (now known as Wingo). This first 3 and a half miles required that five bridges be built, the largest of which was 70 feet in length. Construction of track began at Norfolk, the railroad's port on August 16th, 1876. Norfolk, located at confluence of the Third Napa Slough and Sonoma Creek, an area now known as Wingo, was the site of a gathering of railroad buildings including a wharf, warehouse and car-sheds. On November 24, 1876 this first section of track had been completed.
Mr. Kohn had purchased 554 acres of land on Sear's Ranch about 1 mile West of Sonoma where he intended for a new town to be laid out. Some grading from the crossing towards Kohn's proposed town was completed however, the grade crossing proved to be such an obstacle that the line was unable to proceed. Joseph Kohn would push the construction of his Sonoma Valley Railroad until late 1878 when financial troubles halted advancement. In 1879, the Sonoma Valley Railroad was taken over by Peter Donahue and his San Francisco and North Pacific Railroad. Over the next few years the traces of the Prismoidal Railway began to vanish from the landscape; the repair shop was torn down and the locomotive sold to an unknown buyer and Prismoidal's sole boxcar was converted into a passenger shelter along the railroad at McGill. In 1889, the San Francisco and Northwestern Pacific Railroad began converting their narrow gauge subsidy to standard gauge with the new construction bypassing much of the original roadbed.
Most of this information is taken from PacificNG.com's article about the Sonoma Valley Prismoidal Railway: http://www.pacificng.com/template.php?page=roads/ca/svp/index.htm. You can also read a first-hand account of what it was like to travel in the Prismoidal Railroad!
At this cache you can see a bridge built by the Northwestern Pacific Railroad. This is a unique design, called a Scherzer Rolling Lift Bridge. The bridge was lifted and lowered using a pull chain (which is currently padlocked), to swing the counterweight down and lift the bridge section up. There are many gear reductions that make this possible, but it would take several minutes pulling, if not longer, to rock this bridge up or down. Unlike other minor bridges on the NWP, this one looks like it will still open. Under the counterweight, shielded from the weather somewhat, there is an informal record of bridge openings. The most recent date is from 2007! Beyond the bridge you can see the "ghost town" of Wingo. Wingo has been in the same family since the 1950's and the owner has a cabin there... so techincally it's population 1, not 0.
A note about parking: To access this area, drive down Millerick Rd. off of Highway 121/Fremont Drive/Carneros Highway. Just after the Larson Family Winery, there is a sign saying that from October to May, the next 1.25 miles of the road is closed. I assume this is due to how muddy the road must get during the rainy season. However, on the day this cache was placed (12/28/13), the road was open - likely because we've had no rain! So if the gate is open, you should be able to drive all the way to the main parking area, assuming your car has high enough clearance (it is a rocky, bumpy, potentially muddy, dirt road). If the gate is closed or you're worried about taking your car down the road, you can park just after the Larson Winery and walk. This will add about 1.5 miles (one way) to your trip!