Glenside, Bridge 20, and a Trestle Erased

An undated packet of negatives and prints left undeciphered in a drawer is the impetus behind this update involving a Sacramento Northern, SN, Bridge or trestle that existed early in the 20th century. Noted on the back of a print of the image shown here was written “Bridge 20 Overpass Revision, From West Bank, Upstream East End of Bridge.” Note the electrical transmission tower seen on the hill along the top edge of the image. Also note there is no water seen in this image, or in any of those to follow.

L310-05-Courtesy BAERA, Western Railway Museum Archives, 222057sn, (Image 1 of 21)

The writing on the back of a print of this undated image reads ”Bridge 20 Overpass Revision, West End From East Bank Downstream Side.” At the other end of the trestle is seen a grade crossing, a line of poles on one side of the railway right-of-way, and hills in the background. Some of the trees along the top edge appear to be part of an orchard.

L310-10-Courtesy BAERA, Western Railway Museum Archives, 222060sn, (Image 2 of 21)

For this image, “Bridge 20 Overpass Revision, East End From West Bank 15-Downstream Side,” the number 20 is stamped onto the trestle abutment. Above the track, the overhead catenary wire is clearly seen in this view.

L310-15-Courtesy BAERA, Western Railway Museum Archives, 222061sn, (Image 3 of 21)

Continuing on, “Bridge 20 Overpass Revision, East End From West Bank Downstream Side,” is another construction scene.

L310-20-Courtesy BAERA, Western Railway Museum Archives, 222056sn, (Image 4 of 21)

Another view labelled “Bridge 20 Overpass Revision, West End Downstream Side” looks toward the grade crossing-side on the trestle based on the position of the poles.

L310-25-Courtesy BAERA, Western Railway Museum Archives, 222058sn, (Image 5 of 21)

Here, “Bridge 20 Overpass Revision, West End From East Bank Downstream Side,” shows the other side of the abutment for the same end of the trestle as in the previous image.

L310-30-Courtesy BAERA, Western Railway Museum Archives, 222059sn, (Image 6 of 21)

The most likely location of Bridge 20 can be deduced from this condensed profile of the Sacramento-San Francisco Railroad, SSRR, right-of-way dated Dec. 20. 1928, eleven days prior to its incorporation into the SN Railway, provides bridge numbers. Number 20 corresponds to what would become the concrete overpass just north of the northern-most Glenside Rd. grade crossing. Why numbers skipped in the naming of those in 1928 suggests other previous structures were eliminated prior to this year.

L310-35-Courtesy BAERA, Western Railway Museum Archives, 22974sn, (Image 7 of 21)

These maps from 2024 show the locations of the four bridges to be discussed next. Numbers 19-21 still have a crossing of some type, to be discussed, while the area of trestle site at no. 17 has been filled in.

L310-37-Courtesy Google Maps, (Image 8 of 21)

Bridge 17, the only one close to mile 20 at approximately 20.5, is shown in a south view on the left from June 17, 1940 with a two car train approaching, and Bridge 19 at mile 22.25 with SN 1012 in a north view on the right from June 22, 1940. Both of these trestles were not located close enough to a grade crossing to be candidates for the bridge in question.

L310-40-Wilbur C. Whittaker Photos, Courtesy Arnold Menke and Garth Groff, (Image 9 of 21)

On the left, SN 1012 at Bridge 20 from June 22, 1940 adjacent to the second or northern-most grade crossing of Glenside Rd. at the SN flag stop, with catenary poles to the north of the track consistent with the set of images presented at the outset of this update. However, the overpass here is made of concrete. The image on the right ca. 1950 shows Bridge 21, another overpass not adjacent to a grade crossing. Ref: L, Wilbur C. Whittaker Photo, Courtesy Arnold Menke and Garth Groff; R, Norman Smith Photo, Courtesy BAERA, W. Railway Museum Arch., 218990sn

L310-45-Multiple Attributions, (Image 10 of 21)

Reviewing this map that includes the electrical transmission tower locations in Contra Costa County, the yellow arrow marks to the general location of the tower that would correspond to the one seen in the initial image in L310-05.

L310-50-Courtesy California Energy Commission, (Image 11 of 21)

The red arrows mark two electrical transmission towers present in 2024 that are possible candidates corresponding to the one seen in L310-05. West of these towers, the electrical wires travel above the Lafayette-Moraga Trail, the ex-SN right-of-way in this location, in the vicinity of Las Huertas Rd.

L310-55-Courtesy Google Maps, (Image 12 of 21)

The initial images noted a revision of Bridge 20, but there is no documentation linking that revision with the conversion of the wooden trestle to a concrete overpass. This aerial view from 1928 is the only earlier image found of the Las Trampas Creek crossing in question, orange arrow, and the composition of the bridge cannot be discerned. With some lingering doubt remaining concerning the location of Bridge 20, an effort was undertaken to possibly find another location.

L310-60-Air Photo C165, Courtesy Earth Sciences and Map Library, University of California, Berkeley, Detail, (Image 13 of 21)

Consider that the trestle in question may have been the original Bridge 20 eliminated earlier in the railways operation prior to 1928. This would explain the gaps in the numbering of bridges seen in the chart in L310-45 from 1928. Maybe the original numbering referred to mile 20 from San Francisco? This condensed profile from 1941 would place mile 20 just northeast of the station at St. Mary’s College.

L310-65-Courtesy BAERA, Western Railway Museum Archives, 17804, (Image 14 of 21)

Although a long list of railfan photographers participating in the Nor-Cal-sponsored excursion of Sept. 18, 1949 captured MW 302 in the cut east of the station at St. Mary’s College, Bob Townley also included the location of the mile 20 marker in this northeast view.

L310-70-Robert P. Townley Photo, Courtesy BAERA, Western Railway Museum Archives, 199145sn, (Image 15 of 21)

This east-facing aerial just north of St. Marys College from 1960 shows the abandoned SN right-of-way, red line, the main branch of Las Trampas Creek, yellow arrow, and the feeder creek in question, turquoise arrow. Although there is no trace of any creek crossing from this point forward, it is easy to imagine from the tree pattern that it might have existed previously.

L310-75-Herrington-Olson Photo A-2895, From the collection of the Moraga Historical Society, Moraga, CA, (Image 16 of 21)

The north aerial view from 1945 over the St. Mary’s College campus on the left provides a detailed view of the SN crossing of St. Mary’s Rd., boxed in red. This portion is magnified on the right, revealing what appears to be a creek crossing, yellow arrow, just north of the grade crossing. The orange arrow shows a section of track with a different ballast appearance than the adjacent track, the significance of which is not known.

L310-80-Sappers Collection, Courtesy BAERA, Western Railway Museum Archives, 216441sn, (Image 17 of 21)

This east-oriented vertical aerial from 1928 show the position of the above noted creek crossing, orange circle. This image depicts the creation of Lake La Salle, at his point devoid of water and no evidence for water flowing in from Las Trampas Creek. This would be timed perfectly with the SSRR revision of any bridge downstream.

L310-85-Air Photo C165, Courtesy Earth Sciences and Map Library, University of California, Berkeley, Detail, (Image 18 of 21)

The image of a bridge revision at this location should also be near an electrical transmission tower. Indeed, the left aerial image shows a tower, red arrow, in the expected position. The northwest ground view from May 31, 1951 on the right with MW 302 shows the tower as well, red arrow, and the grade crossing cross buck as well, blue arrow.

L310-90-Google Maps, l, H.M. Stange Photo, Courtesy Krambles-Peterson Archive, r, (Image 19 of 21)

The corresponding southeast views at the grade crossing, however, document that Bridge 20 could not have been at this position. The image on the left from the last Sunday of passenger service, June 29, 1941, with SN 1014 and two trailers shows the poles immediately south of the intersection to be to the right of the track, red arrows, while the detail of the Bridge 20 overpass image shown on the right from L310-10 shows the poles to the left of the track, green arrows.

L310-95-Courtesy BAERA, Western Railway Museum Archives, Richard Jenevein Photo, 69442sn, l, 222060sn, r, (Image 20 of 21)

For now, the evidence shown supports the location of Bridge 20 to be north of the former SN Glenside flag stop, but documentation confirming the transition to a concrete overpass is still needed to complete the story. A north, left, and northwest, right view from 2018 are provided to show the crossing is still part of the Lafayette-Moraga Trail.  For more views of the SN Glenside flagship, proceed to this update.

L310-100-Stuart Swiedler Photos, (Image 21 of 21)