A Chilean man was halfway to freedom when his alleged border-crossing attempt was derailed.

The man, who was deported from the U.S. once before, was using a makeshift cart Sunday to shuttle himself along the support beams of an international bridge over the Rio Grande. But a wheel on the cart broke, stranding him on the span at least 20 feet above the ground, the Border Patrol said Monday.

Agents have been paying particular attention to the rafters of international bridges in El Paso, Texas, since last year when a similarly crude system for smuggling drugs was discovered.

"You can't knock the ingenuity. It's there," Border Patrol spokesman Doug Mosier said.

The man told agents that smugglers in Mexico had arranged to get a group of people across the river using the cart, Mosier said. It is unclear how many people may have used it previously.

This is not the first time that Border Patrol agents have found such a makeshift device, but the discoveries are rare, agency officials told the El Paso Times.

This particular cart had a metallic frame with a wire mesh top. Underneath, the frame was supported by rubber wheels, like those on a toy wagon, mounted on axles, the El Paso Times reported. The cart fit perfectly between two I-beams running four feet apart along the length of the bridge’s underbelly.

Supervisory Border Patrol Agent Victor Lujan told the El Paso Times that an immigrant would lie on the trolley on his back, using his legs to push on the beams to move the cart along the rails.

Rafael Ernesto Corvalan Herrera, 33, was arrested Sunday afternoon and faces a federal felony charge of illegally entering the country after being deported. He is a registered sex offender in Florida.

Corvalan is being held without bond at the El Paso County jail, where records do not show if he has a lawyer. He told agents he paid smugglers a little less than $400 for the cart ride, the El Paso Times reported.

Corvalan said he waited under the bridge for 18 hours before being discovered.

According to law enforcement records in Florida, Corvalan was deported after February 2003 convictions for sexual battery using threats of force or violence, and false imprisonment.

The Associated Press contributed to this report.

Click here to read more on this story from the El Paso Times.