TAPACHULA, Mexico — Unlike many of the migrants who pass through Mexico on the way to the United States, Adolfo Herrera isn't hoping for a new life. He's returning to an old one. He's going home.

Herrera speaks street-worthy English, is a big fan of the Dallas Cowboys and has spent 25 of his 28 years in Texas. He was deported a year ago to his country of birth, Colombia, but felt like a foreigner.

"I don't got family in Colombia. I don't know nobody. I don't want to live there," Herrera said, speaking in a migrant shelter near the border with Guatemala.

"I'm going back to the United States. No doubt, buddy," he said, listing the numerous relatives — from grandmother to brothers — who live near his home in Lewisville, north of Dallas and Fort Worth.

Two weeks ago, the Obama administration announced a dramatic change in U.S. policy, saying it would drop efforts to deport illegal immigrants who have no criminal records. Instead, Homeland Security Secretary Janet Napolitano said Aug. 18, her department will focus on the deportation of convicted criminals and those who might be a national security or public safety threat. Under the new policy, some 300,000 pending deportation cases will now be reviewed in U.S. immigration courts.

That, however, does nothing for those already deported, and many are among the migrants willing to take huge risks to get home again.

"I know it's really dangerous but I have to do this for my children," said Mary Luz Armendariz, a Honduran who was deported from Long Beach, Calif., recently after 18 years there.

Armendariz left her three children, all U.S. citizens, behind with friends, and the phone calls with them have been painful.

"They cry. 'I miss you, Mom. I love you. Why don't you come back?'" she said.

She spoke as she prepared to shinny up a ladder to the top of a freight train known as "La Bestia," or The Beast, at a rail yard in Arriaga, a town in Chiapas state that is the southernmost point in Mexico's rail system. The glow of a rail yard light fell on her face. A bandage wrapped her knee, strained from days of walking.

The migrant journey north has never been riskier. Some fall victim to gunslingers from organized crime groups who halt trains and abduct migrants for ransom. Scores of unlucky ones end up in mass graves. Others are pressed into service as cartel triggermen to do battle with rival gangs. Some simply fall to the tracks off what many call the "trains of death."

Still, they keep coming, many of them propelled by the desire to reunite with family and friends in lives they built in the United States.

Most migrants' trips begin with a benign river crossing — a raft excursion.

Along the Suchiate River that delineates part of the border between Mexico and Guatemala, some 100 rafts made of twin tractor inner tubes lashed to a wooden-slat platform carry passengers and contraband cargo back and forth.

Passengers pay less than $2 to cross the river. Local, state and federal police largely ignore — or benefit from — the illegal trade. It is a free-for-all, a door left wide open.

"The only danger around here is that your raft pops a leak and you take a dip," said a young rafter who would only give his name as Chucho.