Standing on the brink of the precipice, we stared down into a rift in the earth's crust — part of a system of gorges so huge that it could swallow four Grand Canyons. Some 3000 feet below, the Urique River, which had carved out the gigantic canyon, seemed a tiny silver thread.

We were 7500 feet up at Divisadero, Mexico, on the Continental Divide. Our train had stopped to give passengers time to see and photograph the cosmic landcape —an infinity of buttes, mesas and many-stepped canyons writhing toward the blue haze of the horizon.

"Great snakes! Now I know why it took a hundred years to build this railroad," said a tall Arizonan at our side. He was one of the 250,000 tourists a year like us, mostly from the United States, who take this journey — the most dramatic train ride in the Western Hemisphere.

It is the spectacular 17-hour, 400 mile trip from Chihuahua — southwest across the fearsome ranges of the Sierra Madre — to Los Mochis, 13 miles from the Sea of Cortez. The line is the Chihuahua-Pacific, opened in 1961.

Along the route, we saw vast upland ranches, temperate-zone orchards and tropical valleys, lakes full of trophy fish, boomtowns new and old, and almost unexplored mountain chains inhabited by Indians of such speed and endurance that they traditionally hunted deer by running them down on foot. And we did all of this in one week, at uninflated prices!

We are at Creel — a jumping-off place for explorers, hunters, mining prospectors, anthropologists and geologists — where we planned to stop for a few days. For years this was the end of the line. Creel is a fascinating mixture of the cosmopolitan and the primitive.

From our cosy hotel we made half-day hikes into the mountains. We walked noiselessly through cathedral aisles of enormous pines, cliffs towering above us on every side, some chiseled by wind and weather into free-standing columnss 100 feet high. Here and there in a cliff we saw natural caves, many with a low stone wall across the entrance, the overhanging roof black with the smoke of generations of cooking fires.

The railway's passenger service ends at Los Mochis, a clean, bustling city of 50,000, an hour and a half beyond El Fuerte. From there, we took a bus to the end of the line at Topolobampo on the Sea of Cortez.

Topolobampo is a lovely little fishing port dreaming beside a blue, deep-water bay ringed by mountains.

The closing of the Tarahumara gap has opened to the traveler a primitive world of stark beauty and awesome grandeur almost unchanged since the beginning of time.

Balderrama will tell you everything you need to know about accommodations and will offer to make all of your travel arrangements, including all associated plane, train and car reservations.

If you choose to make your own plane reservations, you'll need to get yourself first to Los Angeles, Phoenix, Tucson, Tijuana or Las Vegas.

Bring along clothing appropriate for both Fall and Summer. This means you'll want everything from a jacket for cool evenings to shorts for hot days — including a bathing suit for the hot springs.

As for gear, make sure you bring hiking boots, a daypack, water bottles, a sun hat, plenty of suntan lotion, and more camera film/memory than you think you could ever use in eight days!