It's eight o' clock Saturday morning at the Tijuana train station, and the locals gather to gawk at 250 gringos, most outfitted with expensive cameras and video gear, waiting for a ride. The Tijuana station is not really so much a station as a boarded-up, one-room shack, up to its walls in dried mud, smack next to the border, where the tracks of the old San Diego and Arizona Eastern railroad head from the United States through an oversized, rusty iron gate to go south into Mexico.

This is a special bunch of tourists, having shelled out at least $178 apiece to ride a rickety train from Tijuana to Tecate and on to Campo. The tour organizer, a retired railroader out of Portola who specializes in booking railway tours of the world, calls today's event the "San Diego and Arizona Eastern Spectacular."

The promoter has managed to attract train buffs from around the country to this dusty way-station. It sits next to a small factory, where workmen churn out plaster-of-paris busts of Madonna, Elvis, and Bugs Bunny to be peddled to the tourists at the main border-crossing just a few hundred feet away. When the locals discover the Americans stranded there, small Mexican children appear to sell them gum.

The afficionados have been bused from the Santa Fe depot downtown. While they wait for the train -- which is late making its way into Tijuana from the San Diego Railroad Museum in Campo about 60 miles to the east -- the crowd of mostly middle-aged and elderly men and couples, some with grandchildren in tow, peer through the 20-foot metal fence at the United States side of the border. The hill beyond is studded with state-of-the art motion sensors, listening devices, and floodlights, all part of Operation Gatekeeper, the Clinton administration's war on illegal Mexican aliens.

Every 20 minutes or so, a four-wheel-drive Border Patrol van painted green and white stops along the American side of the border, and its occupants peer back through the gate and exchange pleasantries with the Americans waiting on the other side.

"Where you from?" asks the green-uniformed Border Patrol agent at the wheel. The tourists shout out their replies: "San Francisco!" "Santa Cruz!" "Seattle!"

"Anybody from Colorado?" asks the agent. "That's where I'm from." No one replies and the agent drives on.

On the Mexican side of the border, the tracks are overgrown with weeds, but this isn't any ordinary set of tracks. This is the future route of what certain San Diego politicians like to call the "Jobs Train" and what others, especially South Bay Congressman Duncan Hunter, see as a gateway for more illegal aliens.

To its sponsors, the jobs train would be the climax of a years-long battle to revive freight service along the old San Diego and Arizona Eastern route from Plaster City in the Imperial Valley to just south of downtown San Diego, where thousands of tons of everything from autos to wheat flour would be trans-shipped through a reopened portal to eastern markets. The dream dies hard. It was the same one held by John D. Spreckels, Jim Copley, and a long line of other San Diego mercantilists desperate to catch up with Los Angeles.

The line was built about 80 years ago, then effectively shut down in 1976 when a hurricane swept up from the Gulf of California and washed out key sections in the area east of Campo. Later, it was bought with California gasoline-tax money by the San Diego Metropolitan Development Transit Board as part of its trolley-building deal with Pete Wilson. The MTDB and its leaders, Maureen O'Connor and then-state Senator Jim Mills, dangled the right-of-way in front of the San Diego business establishment as kind of a quid pro quo for permission to build the trolley, and though the trolley was built, the re-opening of the freight line to the east never came to pass.

The latest push has come from Democratic Congressman Bob Filner and San Diego Councilman Juan Vargas, who want to use federal loan guarantees to move the project along. Opposing Congressman Duncan Hunter cites a government report that the train would add to illegal immigration and cost too much. But the biggest uncertainty now comes from the government of Mexico, which owns the 50 or so miles of tracks that snake from downtown Tijuana through the Mexican backcountry and into Tecate, finally returning to the United States just south of Campo.

Mexico City sought to "privatize" its part of the railroad last year, but instead of awarding an operating contract to Railtex, a United States company that runs MTDB's side of the operation, it gave it to a well-connected Mexican-owned outfit called Grupo Morphy. Earlier this year, Grupo Morphy balked at paying its bid price, and the deal is now said to be under "renegotiation."

The mystery of what is going on behind the scenes in Mexico City remains as deep as the unsolved 1994 conspiracy to assassinate Mexican presidential candidate Luis Donaldo Colosio on the streets of Tijuana. Without a permanent operator, there isn't any money to invest in fixing up the picturesque but perilous route through the Mexican countryside, and American politicos are powerless to do anything about it.

Some think the Mexicans are making a point. While it sorts out the Grupo Morphy contract, the Mexican government is allowing Railtex to continue freight runs on the part of the line that runs from Tijuana to Tecate. Especially important to the Mexicans is the fact that Tijuana depends on rail-delivered imports of liquid natural gas -- the city's primary source of cooking and heating fuel -- from the U.S.

Today, though, the tourists own the tracks. The train arrives at the Tijuana station from Campo 50 minutes late, towed by an old Southern Pacific diesel engine. The passengers snap hundreds of photographs as the train eases down the tracks, its horn blaring at every grade crossing. The antique coaches are painted a dusty military brown and look like something the Russian army might use transferring prisoners to Siberia. As the doors slam open, a little old lady decked out in train gear is the first to scramble on.

Once the contingent from America is aboard, the train pulls into the Mexican heartland. Curious Tijuanans stare as the train makes its way through the city and past the modern Tijuana jail. Once the train crosses the concrete-lined channel of the Tijuana River, the city seen through the car windows is big and prosperous. On a distant hill, a huge cathedral's blue domes glisten.

Multistoried apartment houses line the bluff-tops for miles. Factories and warehouses abound: Hyundai, Mattel, Sony. Many have help-wanted signs seeking "ambos sexos" -- both sexes. The so-called maquiladoras, or "twin plants," which make goods bound for the United States, can be seen along the tracks for the first two hours or more, as the train picks up speed. If this is to be a jobs train, then it seems the jobs belong to Mexico.

New districts appear to have sprung up from nowhere. It's a world apart from San Diego. Huge dormitory-like buildings are everywhere. Newly framed residential construction stretches across the hills. The train travels south past giant Rodriguez Dam and into yet another valley, overflowing with new, neatly laid-out industrial parks filled with the factories of multinational corporations. Against the backdrop of the well-painted factories, a few human beings can be seen. One, a middle-aged man, brushes his teeth in the back of a large truck, where he appears to be living with his wife and young daughter. Families wave cheerfully from their hillside shanties. Dogs bark and roosters crow.

Several hours later, an hour or so before Tecate, the engineer comes to a stop halfway up a formidable hillside grade. It is time for the train buffs to get off and take pictures of the dusty train for their collections. Across the valley the toll road to Tecate can be seen, busy with diesel trucks. In the distance, big new gasoline holding tanks mar the otherwise pristine rural scenery. When the photographers are done, the train moves on to Tecate for lunch and a change of engines. When the tourists return, the train is pulled by an old steam engine, built 80 years ago and restored by the San Diego Railroad Museum.

In the afternoon, an hour or so out of Tecate, the train stops for another photo session several miles south of the U.S. border. The tourists file out of the cars and take their position on a steep hill next to the track to wait for the train to back down the hill so it can return around the corner: a perfect shot of belching smoke and steam. The huge engine has trouble getting traction on the weed-covered tracks and must be pushed by the diesel that had pulled the train in the morning.

As the train buffs wait for the problem to be solved, a contingent of Mexican federal police carrying automatic weapons appear on the crest of the hill and begin interrogation of the photographers. After the session is over, they follow the tourists back to the train and stand guard to make sure no stragglers remain behind.

Less than 20 minutes later, the train enters a short tunnel and emerges into the United States, where it stops for what is supposed to be its final photo shoot as it chugs across the 80-year-old trestle.

But U.S. Customs and the Border Patrol are upset that millions of federal dollars have been spent on personnel and high-tech devices to make the border secure. This is the tunnel that Congressman Duncan Hunter fears. If regular freight service along this line is ever resumed, Hunter says, Mexican bandits may use it to enter the country. If tourists can get off the train with impunity, then drug and arms smugglers might penetrate the border. As the 250 or so passengers file off the train and take their positions on a hillside overlooking the tunnel, the conductor's walkie-talkie begins to cackle.

Ten federal agents waiting at the railway museum are demanding that the train continue onto its last stop in Campo and be cleared through customs before anybody can get off, period. Otherwise, says the voice over the walkie-talkie, "a couple hundred people will be in big trouble." A frustrated conductor argues for a bit and then gives in. The amateur photographers are put back aboard and watch from the windows as the train rolls past several complements of grim-faced Border Patrol agents staked out along State Highway 94. They do not return the waves of the tourists.