TULTITLÁN, Mexico -- The rails slice through Tultitlán like freeways, smooth and deceptively straight. Just follow this line, they seem to say, and you'll get to the United States.

The vibrating rails make a singing sound when a train approaches. Within seconds, migrants emerge from culverts or bushes, their worn shoes pounding the gravel, their fingers clutching for a handhold on the hot steel cars.

In the underground world of illegal immigration, this gritty suburb of Mexico City is Grand Central Station, a junction where Central American stowaways change from one freight train to another on a harrowing, often deadly, ride to the U.S. border.

"Some of them come here shaking, grown adults crying after what they've been through," said Felipe Valdez, the priest of the nearby St. Francis of Assisi church.

Mexican railroads are the main means of travel for Central American migrants, who are heading to the United States in rising numbers. The total number of Hondurans, Salvadorans and Guatemalans caught by the U.S. Border Patrol soared from 20,210 to 114,665 between the 2000 and 2005 fiscal years. Mexico itself deported 221,948 people from those three countries in 2005.

Migrants prefer the freight trains over Mexico's long-range buses because the buses have to pass through highway checkpoints where Mexican troops and police search for illegal immigrants. The trains are checked only sporadically, usually by immigration officials at rail yards.

But the journey is longer and filled with ruthless gangs, brutal weather and physical hazards. Many migrants are crushed by overpasses, shaken loose from the speeding cars, or maimed on the rails after falling asleep and losing their grip.

In the Tultitlán neighborhood of Lechería, the main rail line from southern Mexico begins to splinter into the routes that eventually lead to Nogales, Ariz.; Calexico, Calif.; and the Texas cities of El Paso, Eagle Pass and Laredo. Trains screech and rattle through this junction several times an hour.

A small rail yard at the split hosts four or five trains at a time. The rails are littered with trash left by the migrants.

Squatter villages of tar-paper shacks have sprung up between the rails and the surrounding factories. Here, migrants can rent a cot for $3 a night or buy food. But muggers, gang members and drug dealers also prowl the shantytowns, looking to take whatever money the travelers have left.

The less time spent here, the better. Migrants jump off one train, walk 300 yards along a curving track, and board another train headed north. After reaching the border, most cross on foot.

Tultitlán is the halfway point on the way to the United States. By the time they get here, most migrants have been robbed or roughed up by the Mara Salvatrucha gangs that control the southern rail routes. Many have gotten ill from drinking water from drainage ditches, lost fingers or legs after falling onto the tracks, or gotten stranded in the Mexican countryside after catching the wrong train.

In October, a migrant was found strangled along the tracks in Tultitlán, apparently by gang members.

"The trip has been a lot worse than I thought," said Jeffrey Rodríguez, a 19-year-old from Choloma, Honduras, as he rested in the shade of a train car loaded with Ford Mustangs. "I've been traveling for 21 days, and they say the last half is the worst."

Many migrants have never been in a big city, let alone Mexico City, a capital of 20 million people that is the world's biggest metropolis after Tokyo. Many arrive penniless and disoriented.

Mexican immigration officials conduct occasional raids in Tultitlán, but enforcement has lapsed since agents accidentally shot a Mexican passer-by during a botched raid on April 17. Furious residents attacked and overturned two immigration service vehicles.

Most Tultitlán residents tolerate the migrants because many are just passing through and have no intention of staying in Mexico.

"I have brothers up in Texas, so I understand. They're just trying to improve their lives," said Fidel García, who runs a sandwich shop between two rail lines. "But some of them have no idea what they're getting into. You see people who have lost legs and arms because of the train. How are they going to work?"

Stories of terrible brutality are common in Tultitlán. One group of seven men and four women told Valdez, the priest, that they had been kidnapped by gang members and held for days in the mountains on Mexico's southern border. All of them, men and women, had been raped.

Angel Montano, a migrant from Lamatillo, Honduras, said he once saw a train's wheels sever a hand and a leg of a traveling companion who fell onto the rails in Sinaloa state.

Montano was making his eighth journey to the United States by rail. He had been caught and sent back to Honduras seven times, once just a few miles after crossing the border near Nogales.

On this trip, Montano had been stuck in Tultitlán for a month, trying to shake a bad stomach illness before moving on. He had been living under a willow tree, afraid to seek medical help for fear he would be arrested.

"I'm feeling better now," he said. "It's a hard journey, but what can you do? I have a family to support."

Across the rail yard, a whistle blew mournfully and another train began rumbling north.

Reach the reporter at chris.hawley@arizonarepublic.com