Re: Lower Cascade Bridge

For Bridges, see the "Report of the Special Commissioners upon the Central Pacific Railroad of California."
R. S. Williamson, Bvt. Lieut. Col. U.S.A., Major of Engineers, et. al., February 27, 1869.
Bridges are listed at page 8 of this report.

The 1897 USGS topo map is not very detailed.

Also see the A.A. Hart stereoviews of these two bridges:
#249 (96mi) "Lower Cascade Bridge, above Cisco."
#251 (98mi) "Upper Cascade Bridge, above Cisco."
(mileages listed on Hart Stereoviews are East from Sacramento)