In 1880, SP built what is now Track 2 as part of its Sunset Route from Los Angeles to New Orleans. SP rival El Paso & Southwestern, owned by mining giant Phelps Dodge, later built what is now Track 1 as a competing railroad. SP purchased the competing route in 1924 and turned its main line into a second main track.
The Cienega Creek bridge was built by the El Paso & Southwestern in 1912. The bridge not only spans the wash, but also carries the track over the original SP line along Cienega Creek.
It is located 5.3 miles southeast of Vail on Marsh Station Road. Vail is located southeast of Tucson at exit 279 on Interstate 10. The concrete arch highway bridge is listed on the National Register of Historic Places.
Traffic varies throughout the week, but the line sees about 40 trains every 24 hours on average. Freight traffic consists of double-stack containers, piggyback trailers, auto racks, unit grain and coal trains, and general merchandise. Coal trains travel to Tucson Electric Power’s generating station in Tucson. Unit military trains can also be seen running in either direction. Trains tend to sneak up on visitors as the canyon walls muffle their sound, so vigilant radio monitoring is a must.
You will see a variety of motive power on UP’s Sunset Route. The railroad hosts road units on UP’s roster, as well as pool power from BNSF Railway, Canadian National, CSX Transportation, Illinois Central, Kansas City Southern, and Norfolk Southern. Leased power shows up, too.
Amtrak’s tri-weekly Sunset Limited passes six times a week. Eastbound train No. 2 is scheduled to depart Tucson at 8:15 a.m. on Monday, Thursday, and Saturday, while westbound train No. 1 is scheduled to arrive at 6:45 p.m. on Tuesday, Thursday, and Sunday. Both trains usually use Track 1 as it’s more direct than Track 2.
There are three small parking lots near the bridge for visitors to Cienega Creek Preserve. Parking at the bridge requires a permit from the county. Call Pima County Parks & Recreation at 520-877-6158 to obtain a permit at least two business days before visiting.
During the summer months, watch for rattlesnakes and scorpions and be sure to carry extra drinking water. Stay on the marked trails and be aware of your footing. There are sharp cacti and gopher holes in the area.