The Riverside Cement Company built a large plant in the early 1900s in what is now Crestmore, and constructed a rail line south to downtown Riverside. This line was connected to the Union Pacific (Los Angeles & Salt Lake) at the southern end. Later, this line was also set up with trolley wire and connected to the Pacific Electric network (which also served Riverside on a branch). The line was extended north to a junction with the PE main line to San Bernardino at Rialto. This was a PE shortcut for Los Angeles-to-Riverside passengers and freight.
UP later constructed a separate branch to Crestmore from the main line at Pedley (west of Riverside) that is still in service today (2004). The original line served Riverside, East River, Cement Plant (Crestmore), Cedar Street, Bloomington, and Rialto. Most of the this joint UP/PE line was abandoned in the 1940s. A small section at Crestmore remains in service, and a short stretch at the south end remained in place until the 1970s.
UP 2-8-0 #6051 is on display in Riverside's Fairmount Park, which is adjacent to the abandoned route.
The south end had an interesting feature — it crossed the Riverside Freeway (CA Route 91) on a double track girder bridge with an adjacent SP spur that is also now abandoned. The bridge had both SP and UP heralds; this bridge was removed in the 1980s or 1990s. Two blocks north of the freeway the dual branches crossed Lime Street on a wooden bridge that allowed only one lane for car traffic below. This type of bridge is more common in the east and south but was rare for California. It too lasted until the 1980s but is now gone.
See also Riverside Junction to West Riverside.