Correct, it was the Western Pacific Railroad's passenger depot, opened in 1910 and still used until about 1970 when Amtrak took over the WP's "California Zephyr" passenger train. OSF's back dining room is available for special events like weddings or presentations, if you don't mind OSF's food it's a nice place for a dinner or meeting. The building was designed by Willis Polk, better known for his work in the Bay Area, but he did a few Sacramento buildings like the D.O. Mills Bank and the PG&E Powerhouse on the river. Western Pacific was owned by a guy who owned two other railroads, the Denver & Rio Grande Western and the Chicago Burlington & Quincy, and by interlocking all three had a continuous route from Chicago to Oakland. The route through Sacramento was critical because of our industrial connections and riverfront wharf; a branch line ran half a block north of the R Street industrial line to reach Front Street, where WP had its own wharf and served waterfront industries. We were also critical to WP because Sacramento had a large workforce of people who knew how to build, maintain and repair steam locomotives at the Southern Pacific shops. WP put their main shops here in Sacramento (a local group of businessmen bought them some land outside the city limits) so they could poach SP's skilled workers, making Sacramento the only city in the United States with the main shops for two Class I railroads.
Opening day of passenger service on the WP. Note passenger station's northern end on the left.
The Southern Pacific depot fouroheight68 is working on was, in some ways, a response to the WP depot; SP's passenger depot was an 1880s arcade station built on the far side of China Slough next to the Boiler Shop, roughly where the western end of the current passenger platforms are now. WP's depot, and later the union electric depot at 12th & Terminal, were more closely integrated into the city and thus more accessible for commuters. Once the old China Slough was filled, SP built its new depot there in order to be more visible to Sacramento riders. Considering that the size of Sacramento roughly doubled between 1910 when WP opened and the opening day for the new SP depot, a much bigger station was called for.