Cajon Pass

Cajon Pass
Elevation	4,190 ft (1,280 m)
Location	San Bernardino County, California,  United States
Range	San Bernardino Mountains/San Gabriel Mountains
Coordinates	34°18.7′N 117°28.5′W / 34.3117°N 117.475°W / 34.3117; -117.475Coordinates: 34°18.7′N 117°28.5′W / 34.3117°N 117.475°W / 34.3117; -117.475
Traversed by	I-15, Union Pacific Railroad, BNSF Railway

At an elevation of 4,190 ft (1,280 m) the Cajon Pass (pronounced /kəˈhoʊn/) is a moderate-elevation mountain pass between the San Bernardino Mountains and the San Gabriel Mountains in Southern California in the United States. It was created by the movements of the San Andreas Fault. The pass provides an important economic link from the Greater San Bernardino Area and Los Angeles to Victor Valley and the Mojave Desert in the Inland Empire, and northeast to Las Vegas.

Mormon Rocks

In 1851, a band of Mormon settlers led by Amasa M. Lyman and Charles C. Rich crossed Cajon Pass on their way from Salt Lake City to Southern California. In commemoration of this crossing, a section of the pass where the railroad passes through (near Sullivan's Curve) is now known as Mormon Rocks.

Aviation

The Cajon Pass area is known for high wind, turbulence and fog. ^[1] The weather over the pass can vary, from foggy days with poor visibility to clear afternoons where aircraft are bounced by gusting Santa Ana winds that top 80 mph (130 km/h). The wind in this area is predominantly out of the West, although in Santa Ana and other weather conditions it may be out of the north or the southeast. Air spilling over the San Gabriels can cause fairly violent up- and downdrafts. On a normal day, with the wind out of the west, turbulence usually starts a few miles west of Rialto and continues a few miles to the east, growing in strength above the altitude of the mountains and especially over the pass itself near the HITOP VFR intersection. In Santa Ana conditions, up- and downdrafts can become especially violent northeast of Ontario Airport, and turbulence can be experienced all the way east to the Banning Pass (itself known for turbulence.) It's important to note that the mass and wing loading of an aircraft determines its sensitivity to turbulence, so what may seem violent in a Cessna 172 may seem only mild to moderate in a Boeing 747. ^[2] In the 2006 Mercy Air 2 accident, an air ambulance helicopter collided with mountainous terrain near the pass in foggy weather.

Rail transport

Union Pacific Railroad GE Dash 8-40C #9214 leads a freight train up Cajon Pass

The California Southern Railroad, a subsidiary of the Santa Fe Railway, was the first railroad to use the Cajon Pass as a route through the mountains. The rail line through the pass was built in the early 1880s as part of a connection between the present day cities of Barstow and San Diego.^[3][4] Today, the Union Pacific Railroad and BNSF Railway (the successor to the Santa Fe) use this pass to access Los Angeles and San Bernardino. Due to the high volume of trains, noteworthy scenery and easy access, it is a popular location for railfanning, and numerous photographs of trains on Cajon Pass appear in books and magazines about trains. The current Amtrak Chicago-Los Angeles Southwest Chief passenger train travels through the pass.

The Union Pacific Railroad operates and owns one track through the pass, on the previous Southern Pacific Railroad Palmdale cutoff. The BNSF Railway has two tracks and began to operate a third main track in the summer of 2008.^[5] The railroads share track rights through the pass ever since the Union Pacific gained track rights on the Santa Fe portion negotiated under the original Los Angeles and Salt Lake Railroad. The original BNSF (ATSF) line was constructed in 1890 and later roads, U.S. Route 66 and I-15, closely followed this route. The 3.0 % grade is especially challenging for long trains, making the westbound descent potentially dangerous, as a runaway can easily occur if the engineer is not careful in handling the brakes. The second track, built in 1913, makes a two mile (3 km) loop around the hills at a lower 2.20% grade. It once contained two tunnels, but both were day-lighted (removed) in order to add the third main track that runs parallel to the 1913 line.^[5] Speeds of 60 and 70 mph (97 and 110 km/h) are found on either side, but are restricted to 14 and 22 mph (23 and 35 km/h) ascending and between 20 and 30 mph (32 and 48 km/h) while descending.^[5] The third track enables a capacity of 150 trains per day on the BNSF lines.^[5]

Cajon Pass was the site of the San Bernardino train disaster.

Road transport

The Mojave Freeway (I 15) was built through the Cajon Pass and provides a major route from Los Angeles and the Inland Empire to Las Vegas. The freeway runs above and parallel to an original stretch of Historic US 66. This stretch, which is now known as Cajon Boulevard, is a short but well-preserved fragment dating back to a rerouting and widening of the highway in the early 1950s. Only the southbound/westbound lanes are in use; the northbound/eastbound lanes and corresponding bridges are closed to through traffic. It is along this stretch of road, accessible via either the Kenwood Drive or Cleghorn Road exits that some of the best aforementioned trainspotting areas may be found.

The historic Summit Inn, off the Oak Hills exit at the summit of the pass, is a historic Route 66 diner and has been at its present location since 1952. Some maps may show the Cajon Pass as a feature on SR 138, which crosses I-15 south of the summit between West Cajon Valley and Summit Valley. The highest point on I-15 is thus identified as Cajon Summit; however, this does not appear to be common practice on most maps.

Utilities infrastructure

In addition to transportation infrastructure, three high voltage Southern California Edison 500 kV power lines cross the summit as well. These power lines head to the Lugo substation northeast of Cajon Pass and connect to Path 26 and Path 46. Both Path 26 and 46 provide the Los Angeles metro area another source of electricity generated from fossil fuel power plants in the Four Corners region, and hydroelectric dams along the Colorado River.

Natural hazards

During October and November of 2003, a number of wildfires devastated the hills and mountainsides near and around the pass, forcing the closure of Interstate 15. The following winter, rains in addition to burnt vegetation caused a number of landsides to further close the freeway pass.

In addition to wildfire hazards, the Cajon Pass is notorious for wind hazards as well. When it is gusty, it is especially difficult to navigate through it as the Santa Ana winds usually push through that area. The winds sometimes reach gale-force strength. As a result, there are usually high wind advisories as well as road signs posted throughout the area. It is not uncommon to see overturned trucks during such windy weather there.

Cajon Pass gets snow occasionally, sometimes enough to close the pass temporarily. When there is snow, the California Highway Patrol will set up checkpoints on the freeway. Since most Southern Californians are without snow tires or snow chains, they are forced to turn back, or wait until the snow has stopped and the freeway has been cleared of snow.

When there is high wind or snow in the Cajon Pass, it is fairly common for weathermen or reporters for San Bernardino, San Diego and Los Angeles-area televisions stations to do location reports from the Cajon Pass.

The San Andreas Fault passes through the Cajon Pass (crossing I-15 on the south side of the summit) and is responsible for the unique local geography.

References

External links

• El Cajon Pass, Google Maps