The Sunset Route east of West Colton is divided into the following subdivisions:
· Yuma subdivision from West Colton (CP Rancho) to Yuma, AZ
Mileposts are from San Francisco. Dispatching in Southern California is carried out from a joint UP/BNSF Dispatching Center in San Bernardino, CA. From Rancho to Garnet, the line has Two Main Tracks, each signaled for bi-directional usage, with maximum speed 70 mph for passenger trains and 50 mph for freights. Trains from the Palmdale Cutoff can head east from Rancho without entering West Colton Yard. Other trains heading east are leaving West Colton Yard or coming directly from the Alhambra subdivision.
East of Rancho (SP 538, MP 538.5), Rancho Avenue crosses overhead on a bridge. I-10 and Valley Boulevard run parallel to the line on its north side. There are signals at the east end of the Rancho area, as the number of tracks reduces from six to four, and then to two. A little further east, the line crosses the BNSF San Bernardino subdivision at grade at Colton Crossing (MP 538.7, el. 973 ft.), with maximum speed 30 mph on the crossing. At this location, there are two east-west tracks, three north-south tracks, and a connector from west to north. There are many signals covering all possible routes through the crossing. La Cadena Drive passes under the tracks on the east side of the crossing, where the maximum speed is 60-50, after which there is an old SP depot on the north side of the tracks (Colton, MP 539.0) and two extra tracks on the south side. A wye on the south side leads to the old PE track to Riverside, heading south down the middle of a street.
There are more sidings to the south of the line (old Colton Yard), Mount Vernon Avenue passes overhead on a bridge, there are signals at Mount Vernon (MP 539.9), and signals at both ends of 5,740 ft. Ice Deck siding (MP 540.1 and MP 541.3), I-215 passes overhead on multiple bridges, there are two extra tracks on the south side under I-215 and continuing to its east, reducing to one as Hunts Lane crosses at grade with lineside industry on the north side of the track, an extra track still on the south side, space where a track used to curve away between light industry, and a crossover at Loma Linda (MP 541.3, el. 1,080 ft.), where the freight speed limit drops to 40 mph.
Waterman Avenue crosses overhead on a bridge east of the Loma Linda crossovers, followed by Anderson Street, also on a bridge, and Mountain View Avenue crosses on a bridge. The track curves south-southeast, Barton Avenue crosses overhead on a bridge, the line comes alongside San Timoteo Wash (on the track’s north side) and crosses Beaumont Avenue at grade. Whittier Avenue crosses at grade at Bryn Mawr (MP 544.5, el. 1,316 ft.), and the line heads upgrade into San Timoteo Canyon, past the crossover at Redlands X-Over (MP 545.1).
The UP (ex-SP) exit from the Los Angeles basin towards Yuma on the Sunset Route, up Beaumont Hill, climbs the almost 2% grade of San Timoteo Canyon until it reaches the broad 2500 ft. summit of Beaumont Pass. Across the broad valley, located between the 10,000+ foot peaks of San Gorgonio to the north and San Jacinto to the south, are the towns of Beaumont, Banning, and Cabazon (newly expanded to include the Morongo Indians’ casino and hotel. The summit of the line is within the town of Beaumont. From the east side, the line climbs from Indio, which is below sea level, 50 miles further east. The segment from the west, through San Timoteo Canyon, to the summit is 15 miles in length, with Cabazon a further ten miles to the east. The entire western slope is two main tracks, each signaled for bi-directional operation, with high-speed crossovers at two locations. In Loma Linda, the line turns from its easterly heading to a southeasterly heading. The lower reaches of the canyon are still populated with operational citrus groves, but as the line climbs from 1100’ to 2500’ altitude, these give way to scrub and horse farms. From many places on this stretch of track, the 10,000+ ft. summits of Mounts Baldy to the west, San Gorgonio to the north and San Jacinto to the southeast are simultaneously visible.
At MP 546.1 there is a road crossing of San Timoteo Canyon Road, and a set of intermediate signals at. Redlands (MP 546.5), where the passenger speed limit drops to 50 mph. Traveling east along the railroad, the line turns east again and the next infrastructure elements are Intermediate Signals, the Alessandro Road grade crossing at MP 548.2, and the crossover at Ordway X-Over (MP 549.3, el. 1,527 ft.), where the passenger speed limit is 40 mph. (All MP numbers on this stretch of line are measured from the location of the former Southern Pacific headquarters at 65 Market Street, later 1 Market Plaza, San Francisco.) Continuing east, there is a set of Intermediate Signals, signals controlling the switch to the Ordway Spur (a short length of line on the south side of the main tracks with access at the west end) at MP 551, where the passenger speed limit is 45 mph, and another road crossing at MP 551.24. More intermediate signals follow at El Casco (MP 552.7, el. 1,828 ft.), followed by a crossover at El Casco X-Over (MP 554.1), with another crossing of San Timoteo Road at 554.9. The line now angles east-northeast until it reaches Beaumont.
At MP 556.8, there is a dragging-equipment and hotbox (overheated wheel bearing) detector. This comprises a silver-painted metal equipment cabinet with a collocated metal antenna tower for radio transmissions to train crews, a set of instrumented flaps between and alongside the rails to detect dragging equipment, and a set of upward-facing infrared detectors to detect the hot bearings. Early detection of either of these phenomena can help prevent train derailments. There is a crossover at Hinda (MP 559.0, el. 2,188 ft.). More intermediate signals follow. There are bridges where the SR 60 freeway crosses overhead, and detectors at MP 560.7.
West of Vaile Avenue in Beaumont, near the top of the hill, is a spur track on the south side, used to hold helper locomotives between assignments. Its exit is at the west end of the spur, controlled by a set of signals. The road crossing is at MP 561.8 (el. 2,569 ft.). On the north side of the track east of the road crossing are the Robertson cement plant, the former Beaumont depot (MP 562.0), now used as a UP Signaling Maintenance facility, and a trailer for the Signaling Construction facilities. Immediately east is the California Avenue road crossing at MP 562.2, and the crossver at Beaumont X-Over (MP 562.3. The line now runs due east for the next ten miles or so. Tri-light signals have replaced ex-SP searchlights as the Two Main Tracks have been extended east of Beaumont to Garnet.
The tracks reduces to a single line, CTC, at Apex, MP 563.2, the summit of the line from both directions, with extra track on the south side. Here, the eastbound climb at a maximum of 1.89% turns to an eastbound descent at a maximum (but not right here) of 1.99%. At Highland Springs Avenue, there is a road underbridge. There is another detector at MP 564.3, with a golf course alongside to the south, the 6,498 ft. siding at Pershing (MP 565.5, el. 2,505 ft.), where the freight speed limit rises to 50 mph, the Sunset Avenue road crossing at MP 566.2, within the siding, followed by the 22nd Street road crossing at 566.9, the Highway 243 road underbridge, the 5,991 ft. siding at Banning (MP 568.2, el. 2,328 ft.) and the Hargrave Street road crossing at MP 568.8.
Next heading east is a detector at 570.0, intermediate signals at MP 570.2 and at Owl (MP 571.5, el. 2,030 ft.), a spur into a gravel plant at MP 572.0, the Apache Trail road crossing at MP 572.6, and the 16,217 ft. siding at Cabazon (MP 574.1, el. 1,789 ft.), where there is also a spur on the north side of the main tracks at a Maintenance of Way staging location. This line was one of the first places that CTC was installed (during WWII) in order to increase train capacity. The signal maintenance building at Beaumont is the site of the original CTC dispatcher office, until it was combined with the other Los Angeles division dispatching desks.
The line continues due east, past the 17,155 ft. siding at Mons (MP 576.2), where there are windmills on both sides as the eastern end of the pass is reached, and the speed limit drops to 45-40, a crossover within the siding at Mons X-Over (MP 576.5), the 11,373 ft. siding at Fingal (MP 578.6), where the line starts to curve a bit and the speed limit is 45 mph for a short distance, with Mount San Jacinto directly to the south, Intermediate Signals, a detector at MP 579.6, two bridges over drainage channels, Intermediate Signals, road bridges overhead as the road to Palm Springs crosses from the north side west of here to the south side east of here, a curve to the southeast past the 6,460 ft. siding at West Palm Springs (MP 582.7), windmills alongside to the south, a curve east again past Hugo (MP 584.4) and a detector at MP 584.5, Intermediate Signals, a 17,121 ft. siding on the south side, where there is extra track on the north side, and the passenger speed limit rises to 55 mph.
There is an Amtrak station (for "Palm Springs") on Garnet siding, on the south side of the line, with the depot on the south side of the siding, a parking lot to its south, and a road bridge overhead to its east, the end of the siding at Garnet (MP 588.1) in June 2008, part way along the siding, and the line turns southeast, now shielded from the wind, on both sides, or sometimes only on one side, by rows of eucalyptus trees specially planted by SP late in the 19th-century.
The line continues southeast, with the speed limit rising to 79-60, on its steady descent across the desert floor, with I-10 alongside to the northeast, past a detector at MP 589.9, a 6,833 ft. north side siding at Salvia (MP 590.6-592.0), two road bridges overhead, a 5,979 ft. north side siding at Rimlon (MP 594.9-596.1), an acute angle road bridge overhead, a 21,029 ft. north side siding at Thousand Palms, starting at MP 598.6, with a road bridge overhead, a crossover at Thousand Palms X-Over (MP 600.5), a road bridge overhead, and Intermediate Signals at MP 601.2, and ending at MP 602.6, two sets of Intermediate Signals, a 6,361 ft. north side siding at Myoma (MP 606.3-607.6), where there is a road bridge overhead and the speed limit is 79-70, a detector at MP 608.5, a divided road alongside to the south, a through girder bridge over a wide arroyo, West Indio (MP 609.6), where CTC ends, the line becomes Double Track, Automatic Block Signals, and the speed limit is 30 mph through the switch from one track to two, and two road bridges overhead, to Indio (MP 610.9, sea level), where the speed limit is 50 mph, there are Intermediate Signals at MP 611.1, spurs on the south side, the remains of four stalls of he roundhouse on the north side of the line, a road bridge overhead, and a grade crossing, with a street still alongside to the south, and Indio Yard (MP 611.3), which once a major SP sorting facility, that was substantially downgraded once the West Colton Yard opened, and now is almost non-existent.