OVER THE MOUNTAINS AND THROUGH THE PAST.

Byline: Story by Eric Noland Travel Editor

THE VINTAGE Auto Club map, printed in 1917 (the same year American troops began arriving in Europe to help end the Great War), offers clues as to just how precarious it once was to drive an automobile north out of Los Angeles.

The map identifies the steepness of the grade at different points, and the precise elevation of various landmarks - vital intelligence for anyone relying on the tinker-toy engine of a Model T Ford for passage through the mountainous Tejon Pass. The map alerts motorists to remote locations where gas and oil are available, or food or a bed to ease white-knuckle strain.

This was the Ridge Route, an aptly named pioneer of a road that served as a forerunner to what is now Interstate 5 (which would be cut through a valley some distance to the west). From 1915, when the Ridge Route was finished, to 1933, when it was bypassed, it was the only way for motorized conveyance to chug north from Los Angeles to California's Central Valley and points beyond.

Incredibly, it's still up there in the hills, pock-marked but passable, and recently gained the protection of the National Register of Historic Places. The Old Ridge Route awaits any intrepid soul with a curiosity about long-abandoned highways - and a reasonable wheel-base clearance.

The road squiggles 37 miles from Castaic to Gorman, about 20 of which is over the ragged ruins of the original roadway. It can provide a road trip of nostalgic dimensions or, given a generous allowance of extra travel time, can be incorporated into a trip to Sequoia, Yosemite or the Gold Rush country.

From northbound I-5, exit at Parker Road in Castaic and turn right at the bottom of the off-ramp, at a green street sign that says Ridge Route. After passing a new housing development, you'll parallel I-5 for a few minutes, then begin your climb into the mountains. Soon, I-5 dips far below to the west, then disappears from view altogether.

After nine miles, immediately after crossing the Templin Highway, you'll come to a gate. Proceed on through, ignoring the yellow sign that warns that the road does not go through (it does). At this instant, you've begun to wheel back in time. Way back.

The concrete roadway that is visible in spots - certainly through potholes that can run to 5 feet in diameter - was poured around 1920, later to be covered with asphalt. In some stretches, where it has washed away, you'll find gravel or bare dirt.

The narrowness of the road might seem claustrophobic, but 20 feet of width was considered plenty for the vehicles of the day. Today, the snugness of the passage is enhanced by shrubs and trees that have begun to crowd in from the sides, or sprout from cracks in the middle of the road, in their relentless quest to retake this terrain. Occasionally, you might have to squeeze around boulders that have rolled down from the cuts. At one point, we encountered a forlorn tumbleweed, sitting smack in the middle of the road.

You'll see electrical power poles along the way but few other signs of human habitation. Keep your eyes open for evidence of the Ridge Route's busy heyday, though. The stone foundation and buttresses of a former roadside hotel command a hillside 22 1/2 miles from Castaic. We stopped here for a brown-bag lunch, finding a protected spot out of a stiff winter breeze. On the top step of the crumbling front stairs, the hotel's name, Tumble Inn, is faintly visible, obviously etched into the wet concrete with an index finger.

A little farther on (26 1/2 miles from Castaic) are the ruins of Sandberg's Summit Hotel, now overgrown by sage, Coulter pine, valley oaks and incense cedars.

It's mind-boggling to think that these two tourist oases would have represented a full day's drive from L.A. back in the early 1900s. Those motorists crept around hundreds of tight, often-blind curves at 15 mph, fretting over the tempest in their radiators or that ominous smell emanating from their brakes.

The travelers probably couldn't permit themselves the luxury of enjoying the views, but in the comfort of a modern SUV, you can. The road often treads along the precise spine of the ridge, and the views in all directions are terrific. You can gaze on the sweep of the Santa Clarita Valley at the beginning of the drive, later on the rugged slopes of the San Gabriels to the east, or the Tehachapis to the north. Any day now, the hillsides will be bursting forth with wildflower blooms. Pull off the road onto any number of ancient turnouts and you'll spot three different lakes: Castaic, Pyramid, Quail.

One key advisory: After inclement weather, the U.S. Forest Service, which maintains the road, might close one the gates because of washouts or rocksteps and try again another day.

OLD RIDGE ROUTE

Where: Castaic to Gorman; 37 miles total. From I-5 north, exit at Parker Road and turn right onto Ridge Route.

Cost: f you plan to stop along the way, pick up a Forest Adventure Pass ($5 per day), available at U.S. Forest Service offices and at some sporting goods stores.

Information: Proponents of the road maintain an informative Web site at www.ridgeroute.com

CAPTION(S):

2 photos, map

Photo:

(1 -- 2) Until 1933, the bucolic Ridge Route represented the only way north out of Los Angeles for automobile drivers. Below, the remains of the Tumble Inn, a roadside hotel, sit among the tumbleweeds.

Roger W. Vargo/Staff Photographer

Map:

RIDGE ROUTE

Gregg Miller/Staff Artist