Friday, June 21, 2019

Bridges: Dougherty Extension Railroad

Close-up of the Boulder Creek bridge as its heads north,
from a panoramic photo of Boulder Creek.
[Bruce MacGregor, A Centennial]
Grading and rail-laying crews working for the Santa Clara Valley Mill & Lumber Company in the spring of 1888 had quite the challenge before them. The company's new mill was to be located four miles north of Boulder Creek along the San Lorenzo River, with a stop for the Cunningham & Company mill two miles north of town. But to get to these two sites, the river and several significant creeks needed to be crossed, in the former's case several times. Beyond the company's mill, one more major creek was encountered before the river began zig-zagging through an ever-narrowing canyon as it reached its headwaters. Here, too, grading crews had to build bridges of increasingly crude quality until the final logging camp was reached eight miles north of the line's junction with the Southern Pacific Railroad yard.

W. S. Rodgers survey map of Boulder Creek, 1905. [UC Santa Cruz Digital Collections]
The line's first obstacle was the triple threat presented by Boulder Creek, the San Lorenzo River, and Bear Creek just north of the yard. Creating the so-called Turkey Foot, these three waterbodies twisted and turned into each other, forcing bridge engineers to cross all of them just to reach the relatively even grade on the opposite side.  Winfield Scott Rodgers' survey map of Boulder Creek shows how these crossed heading north at a northwest angle, cutting through a small housing subdivision and crossing Bear Creek Road (then known as Park Avenue). A snippet of a panoramic photograph  of the town shows the first of these bridges, which appears to be a rather simple design with an open wooden deck upon which two tracks merged just before reaching the midpoint of the bridge. The structure of the bridge beneath the deck is unfortunately not known nor is the composition of the other two bridges, although they were probably similar in style.

The short truss bridge crossing the San Lorenzo River south of Wildwood, c. 1910s.
[Rick Hamman]
The right-of-way continued on the east side of the San Lorenzo River, where it required a bridge of an unknown type over Two Bar Creek 1.2 miles north of the Turkey Foot. The next significant and documented structure is located 0.7 miles north of that, just north of the Cunningham & Company mill, where the Dougherty Extension Railroad crossed to the west bank of the river for the second time. The bridge used here was perhaps the highest-quality of those along the line. It was a redwood framed Pratt truss span that may have been designed to support standard-gauge trains. The bridge was likely a later addition, replacing an earlier unknown structure, and may have been added in the early 1900s, when Southern Pacific was considering purchasing and upgrading the route to build a line to Pescadero. It became an iconic set-piece in Wildwood marketing in the 1910s and appears in several photographs from the time.

At the Santa Clara Valley Mill & Lumber Company mill, located 1.4 miles to the north of the Cunningham & Company mill, the last photograph bridges can be found. While one track wrapped around the river, avoiding the need for bridges, the main line crossed the river twice in order to access and then proceed beyond the mill. These bridges were much more crudely built, composed largely of cut redwood tree trunks with crossties set atop them. Despite this low-cost design, the bridges were incredibly robust and were able of supporting large lumber trains leaving the mill. Two such bridges sat at the south of the mill, crossing the river roughly parallel to each other.

Dougherty Mill #2 at Riverside Grove, with two trestles barely visible in the photograph. The San Lorenzo River Trestle is at left beside the ox bridge while a second trestle is visible at right heading over a small creek. [Rick Hamman]
Remnant trestle at Riverside Grove, late 1970s. [Rick Hamman]
To the north of the mill, another bridge of similar design crossed the river as it meandered back to its original alignment around a U bend. Rick Hamman photographed the remnant of this bridge in the late 1970s, although it has since disappeared, probably due to flooding in 1982. In this photograph, it is clear that large logs also held the bridge aloft from below, providing it with extra support. A vehicular bridge originally ran beside this structure allowing access to the mill from the north. The mill pond sat directly beneath the bridge, undoubtedly causing problems when pond levels were too high since the river is not especially deep in this area.

Beginning in 1893, the Dougherty Extension Railroad began snaking up the San Lorenzo River, ultimately reaching its headwaters four miles further north around 1898. None of these bridges were photographed but remnants of some of them show that most were of a similar design to those at the company mill. The railroad first crossed over the river a fourth time roughly 500 feet north of the mill, near modern Bean Avenue off Teilh Drive. A spur broke off about 0.6 miles to the north to go up Feeder Creek and the Chase Company Mill. This bridge probably had a rather interesting design since it had to cross a broad and deep ravine created by the confluence of the creek and the river. Just slightly to the north, the main line crossed back to the west side of the river near Fern Drive to access the logging camp at McGaffigan Switch.

North of this crossing, the line remained on the west bank until just beyond Waterman Switch, roughly 2.0 miles from the Feeder Creek spur. How many times the railroad line crossed the river in its final two miles is unclear and may never be known with certainty. The river winds a lot in this area, and the ever-narrowing valley forced the track to criss-cross it constantly. These bridges would have been of extremely crude quality, in most cases simply logs tossed across the river with tracks placed atop them and packed dirt abutments on either end. The track likely crossed four times before reaching its end. Bridges and culverts to span smaller bodies of water were also likely required across the entire right-of-way from Boulder Creek.

Access Rights:
Nothing survives of any of the bridges except one very degraded structure inside Castle Rock State Park near the San Lorenzo River's headwaters. The bridges north of Wildwood may have been removed as early as 1913, when this section of track ceased to be used. The bridges further to the south were removed in 1917 when the rail was scrapped. Access to most of the bridge sites are via private property, although parts may be seen from various roads in the area. Nonetheless, little to nothing survives of these crude redwood-built structures. Trespassing is not encouraged.

Citations & Credits:

5 comments:

  1. The 1916 photo with the three people walking the track looks just a little like Brookdale, but not in 1916 due to the narrow-gauge and all those taller trees. There is probably a good reason to say no; I, however, see a similar bridge, a clearing with a large dark tree on the other side, and a peculiar slant to the sunlight and shadows (as if the track was angled into the west). I wouldn't know the area around the Wildwood trestle though, and may lose the observation because a wooden truss has more visible notches and the curvature of the track doesn't correspond (and is too overgrown with weeds).

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    1. It's definitely not Brookdale. The trestle there was much longer and the approach was a narrow cut. The direction of the Wildwood Trestle was roughly the same alignment as the Brookdale Trestle, which may explain the similar lighting. This trestle was also the last of those create for passenger service. Those north of this site were reserved for freight-(and workers-)only. I apologize for the low quality. It is a photo of a photo of a photo taken in poor lighting conditions.

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  2. Passenger service, that explains the tilted curve a little better; which was another reason I felt it was a mislabeled photo. While there is always some banking of the curves, this track seems to have had faster trains in mind rather than pure lumber. I believe that curves were built this way to relieve binding and wear, increasing it to help stability and traction as speeds increased, but I could be somewhat wrong.

    (I also noticed a lack of overhead communication wires [code lines?].)

    I wonder if the bridges at Brookdale and Ben Lomond could be backdated as an earlier narrow-gauge construction? If there was enough room and support, the mystery of the wooden bridges might become known. The simple trestles at each end would need an entirely new design, but maybe it was easily accomplished.

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    1. Well everything north of Boulder Creek was private Santa Clara Valley Mill & Lumber Company rails, so they may have routed telegraph service elsewhere or just not had it at the mill.

      The bridges at Brookdale and Ben Lomond could certainly be earlier bridges that were either built with standard-gauge in mind or were easier to expand. As the bridges were replaced in the late 1890s, they were upgraded to standard-gauge in expectation of the conversion. The first to get upgraded was the Clear Creek Trestle, which had at least one concrete foundation built, but that doesn't mean the other bridges weren't upgraded soon after with other types of material.

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  3. this is all excellent research and info;
    as a railroad buff i greatly appreciate
    the time and effort that you have put
    into it- it is a shame there is so little left; thanks a million! jim brewer

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