The lumbering freight train known as "The Beast," a key part of the route for migrants heading north to the United States, rolled to an abrupt, unscheduled stop in the black of midnight.

Mexican federal police and immigration agents had waited silently in the brush alongside for at least hour, visible only by the glint of their powerful flashlights.

As the train stopped, the area was suddenly flooded with spotlights as agents pounced from both sides of the track, scaling ladders to the tops of the freight cars and shouting: "Federal police! Give up! You're surrounded! Come down carefully!"

About a dozen men, some literally spitting with anger and desperation, were firmly led off the track, an agent's hand on the back of their necks neck, and taken to waiting vans for processing and deportation. Agents helped a lone female migrant clambering over a coupling between cars to reach their van, telling her "Walk carefully, don't fall."

"Don't touch me," she snarled.

The scene early Friday would have been unheard of in Mexico during the decades in which Central American migrants were allowed to freely hop freight trains to reach the U.S. border. But the raid is part of a crackdown that has sharply reduced the number of women and children trying to make their way to the United States, where they turn themselves into the U.S. Border Patrol — an exodus that caused what U.S. leaders call a crisis at the border.

Fewer than 15 migrants were detained Friday on a train that once carried 600 to 1,000 migrants at a time. It seemed — at least temporarily — like the end of an era for the train the migrants dubbed "La Bestia" because of all the travelers who had been maimed or killed trying to hitch a ride.

But the migrants, fleeing unemployment, violence and poverty in their home countries, have been only temporarily deterred by past strategies. Some already have devised ways to avoid capture under the new crackdown. One lone migrant escaped Friday's raid by lying flat on the roof of the last freight car and managing to stay aboard as the train pulled out.

Police said the most experienced border crossers wait near the back of the 50-car train, where they have more time to react when it stops.

They know it's hard for police to patrol the entire length of the train.