Ferrocarril Sonora–Baja California

The  Ferrocarril Sonora–Baja California is a former railroad line of Mexico that built the line from Mexicali, Baja California, to Benjamín Hill, Sonora in 1948. It interchanged with the Southern Pacific Railroad at Calexico, California, and with the Ferrocarril del Pacifico in Benjamin Hill, Sonora. Before 1960, The SP-controlled Inter-California railroad provided trackage rights for the SBC from Pascualitos to the International Border. SBC took control of that part after the demise of the Inter-Cal.

SBC provided passenger and freight service throughout its existence. It was headquartered in Mexicali, B.C. and had major repair and overhaul shops for its equipment in the town of Benjamin Hill, Sonora. From 1970 into the FNM merger, the SBC also controlled the 44-mile freight-only "Ferrocarril Tijuana y Tecate" UB line from border to border. SP, Kyle Railways and later the San Diego and Imperial Valley Railroad operated the line, paying a fee to the SBC, and later to FNM.

It was absorbed into Nacionales de México in 1987, thus becoming a fallen-flag. The last passenger train from Mexicali to Benjamin Hill operated in 1997. Today the line continues to provide daily modern freight service, including intermodal. It is now known as Ferromex's Puerto Penasco Subdivision and designated by the SCT as the "U" and "UA" lines of the Mexican rail system.