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. 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.). At this location, there are two east-west tracks, three north-south tracks, a connector from west to north and a connector from south to east which joins at Riverside Lead (MP 538.8). 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, 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 crossovers at Loma Linda (MP 541.3, el. 1,080 ft.).
Waterman Avenue crosses overhead on a bridge east of the Loma Linda crossovers, followed by Anderson Street, also on a bridge. There is a detector and the Bryn Mawr hold signal at MP 543.1, el. 1,203 ft.,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 MP 544.5, el. 1,316 ft., and the line heads upgrade into San Timoteo Canyon.
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. Signals on this section of track each have two hooded searchlight signals arranged vertically on a single background ‘target’. Hoods and target are painted black. Each signal has a sign that states the milepost at that location and a digit indicating which individual signal the sign refers to (or which track that signal controls). Where there are signals facing both ways at a particular location, the “milepost” numbers, nominally set at tenths of miles, are one unit (tenth) apart to provide unique identification. For example, the signals between MP 558 and MP 559 are labeled 5583-1 and 5583-2 for the west facing signals on tracks 1 and 2 respectively, and 5584-1 and 5584-2 for the east facing signals on tracks 1 and 2 respectively. (On the signs, the digits are arranged vertically, with a horizontal line representing the ‘dash’.) The set of signals at MP 546.1 has a third set of signals on each post, lower than the standard west-facing and east-facing signals, facing downhill (west-facing) only, and thus impacting only uphill traffic. (The lower head is often to give the “double yellow” or General Code of Operating Rules Rule Number 9.1.6 “Approach Diverging” to indicate that the next signal has an aspect that will authorize the train to take a diverging route, in this case the crossover.) Signals on this stretch of line are controlled by a combination of track circuits and a Dispatcher working at a computer console in the joint UP/BNSF Southern California Dispatching Center located a few miles away in San Bernardino.
Pairs of lifting barrier gates protect the public road crossings on the western slope. Each road crossing at grade is controlled by approach circuits on the track, and activated by electronics in a silver-painted control cabinet. The electronics respond to the speed of approach as well as proximity of the approaching train, and bring down the gates at approximately the same time before arrival of the train, no matter what the speed. Each of the cabinets includes a notice listing the name of the road, the milepost, and the phone numbers to call in the event one or more vehicles is blocking the track. The signals are only incidentally at this point, and are not in any way interlocked with the gates.
Traveling east along the railroad, the line turns east again and the next infrastructure elements are Intermediate Signals at MP 547.1/2/3/4, and the high-speed crossovers at Ordway (MP 548.1, el. 1,527 ft.), located immediately to the west of the Alessandro Road grade crossing at MP 548.2. These crossovers use switches of the ‘moveable point-frog’ variety, where the open end of the points are controlled by one switch machine and the frogs at the closed end are adjusted by another switch machine to close the gap that would exist with fixed frogs, to reduce the pounding and damage to the frog as wheels cross the flangeway gap. As there are two crossovers at this location, there are four switches, each of which has the moveable point frog, and each of which has a sign to that effect at both ends of the switch. All four switches are operated using electronics located in a sliver-painted metal cabinet that has a sign indicating the name of the ‘Control point’ (in this case, Ordway) and the milepost number corresponding to that location. 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.) The signals at crossovers have heads facing away from the crossovers only (unlike the intermediate signals), with each pair of crossovers having four sets of signals, one for each track at each end of the switches. Each signal has two sets of two-light signals with separate targets for each pair of lights, arranged vertically above one another on each post (thus, for each track, at each end of the switches).
The crossing of Alessandro Road is outfitted exactly the same way as the one of San Timoteo Road, described above. Continuing east, there is a set of Intermediate Signals at MP 550.2, 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, and another road crossing at MP 551.24. More intermediate signals follow at 552.8 (El Casco, el. 1,828 ft.) and 554.6, with another crossing of San Timoteo Road at 554.9. At various places along these tracks, such as near 555¾, there are unlabeled metal ‘huts’ that appear unconnected to any particular operational element of the railroad. The high-speed crossovers at Hinda,(MP 556.8, el. 2,188 ft.), appear identical in every way to those at Ordway. The line now angles east-northeast until it reaches Beaumont.
At MP 558.0 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 are more intermediate signals at 558.3/558.4. This set of signals also has a third set of signals on each post, lower than the standard west-facing and east-facing signals, facing uphill (east-facing) only, and thus impacting only downhill traffic. More intermediate signals, without the additional set, follow at 560.2/560.3. There are bridges where the SR 60 freeway crosses overhead.
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 resembles the others, and is at MP 561.8 (el. 2,569 ft.), the same location indicated from the Beaumont crossovers immediately to the east of the road crossing. On the north side of the track east of the road crossing are the Robertson cement plant, the former Beaumont depot, 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. 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.
There is a set of intermediate signals and an unassociated road crossing at Apex, MP 563.2, the summit of the line from both directions. 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, Intermediate Signals at MP 565.2, the Sunset Avenue road crossing at 566.2 and the Pershing intermediate signals at 566.5 (el. 2,505 ft.), where the east and west facing signals are separated by some distance (in July, 2006), followed by the 22nd Street road crossing at 566.9, the Highway 243 road underbridge, crossovers at Banning (MP 568.4, el. 2,328 ft.) and the Hargrave Street road crossing at MP 568.8.
Next heading east is a detector at 570.0, the intermediate signals at MP 570.2 and at Owl (MP 571.5, el. 2,030 ft.), a spur into a gravel plant at CP Robertson, MP 572.0, the Apache Trail road crossing at 572.6, and the crossovers at Cabazon (MP 574.2, 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 originally single track. It is 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. From the 1960s to the present day the SP and UP have gradually expanded the double track (usually tying together sidings), barely keeping up with the rising traffic levels. The line carries more traffic in 2004 than any previous year.
The line continues due east, still Two Main Tracks, speed limit 50 mph, past Mons (MP 576.2), where there are windmills on both sides as the eastern end of the pass is reached, Intermediate Signals at Fingal (MP 578.8), 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, two bridges over drainage channels, Intermediate Signals at MP 580.1/2, 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 West Palm Springs (MP 581.7), where there are Intermediate Signals, a detector at MP 582.6, where the speed limit is back to 50 mph, Intermediate Signals at MP 583.x, windmills alongside to the south, a curve east again past Hugo (MP 584.4) and detectors at MP 584.5, Intermediate Signals at MP 586.0, a 5,268 ft. siding on the south side at West Garnet (MP 587.9), where there is extra track on the north side, and the speed limit rises to 60 mph. There is an Amtrak station (for "Palm Springs") on Garnet siding, on the south side of the line, where there are new signals, still facing sideways, in October, 2007, 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 Two Main Tracks reduce to single track, CTC, at Garnet (MP 588.3), 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 on its steady descent across the desert floor, with I-10 alongside to the northeast, past the end of the depot siding at East Garnet (NP 589.0), the former location of a detector at MP 589.9, a 6,833 ft. north side siding at Salvia (MP 590.6-592.0), where the speed limit rises to 65-60 mph and there is a road bridge overhead, MP 594, a road bridge overhead, a 5,979 ft. north side siding at Rimlon (MP 594.9-596.1), a detector at MP 598.0, where the speed limit rises to 79-65, an acute angle road bridge overhead, a 20,499 ft. north side siding at Thousand Palms, starting at MP 598.6, with a road bridge overhead, crossovers at MP 600.6, a road bridge overhead, and ending at MP 602.6, Intermediate Signals at MP 604.x and at MP 605.2, 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 spurs on the south side with wood products cars (in July, 2006), 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.
Operation of trains over Beaumont Pass is very challenging: uphill trains are of course fighting gravity; their speeds limited by the amount of horsepower and to no small degree by headwinds on the east side. By the time a train gets to the top of the grade it is vested in an enormous amount of gravitational or potential energy.
Downhill trains have greater challenges: the potential energy must be dissipated by air brakes (friction against the wheels) and dynamic brakes at a safe rate such that wheels or resistor grids (on the locomotives) are not overheated. The faster a train goes down a grade the faster this energy must be dissipated: a runaway train is the result of speed exceeding the ability of the brakes to change potential energy into heat and instead the energy goes into kinetic energy and the train accelerates. Absent friction (not a bad assumption for a roller-bearing train) a train that drops 125 feet in elevation (about 1-1/4 mile on these grades) will accelerate to 60 MPH, and this will happen in about 2-1/2 minutes.
Speeds of trains going downhill are adjusted depending upon the weight of the train and the number of “operative brakes” on the cars and the number of axles of dynamic brakes on the locomotives. Often the speed of downhill trains is restricted to less than the same train going uphill. Another consideration is the stopping distance and signal spacing; trains must be able to stop from their authorized speed in the distance between signals (e.g. upon seeing a yellow signal the engineer must be able to stop before the next signal, which is likely to be red).
In prior years, the Southern Pacific literally “wrote the book” on safe train handling on mountain grades such as Beaumont, Donner, and Tehachapi. (A crude approximation of these rules is the old truck driver’s practice never to go faster down a hill than you can go up that same hill.)