Arriaga, Mexico (CNN) -- The first thing you notice about Jessica Ochoa is her huge brown eyes.
She's a petite Salvadoran and was coming up to her 21st birthday when I met her in the southern Mexican border town of Tapachula.
The next thing you notice is her stiff walk. Her right leg was severed in February 2009, when she fell off a cargo train. The train's steel wheels did the rest.
By the time she reached the hospital, doctors say, she'd lost almost half her blood. What was left of her lower right leg and foot lay by the side of the tracks in a sock and tennis shoe.
Like thousands of other illegal migrants every year, Ochoa had been heading to "El Norte," which in Spanish translates as "The North" but means the United States.
Her American dream was to work hard and gradually save enough to buy a brick-and-concrete home for her mother to replace the tin shack where she lives with the rest of the family in a working-class neighborhood of San Salvador.
Only the poorest of the poor dare to ride aboard the lumbering cargo train that sets out from the station at Arriaga, in southern Mexico, every couple of days or so. They have little choice. This is a free though perilous ride, and they have no money.
Most of the migrants come from Central American countries like Guatemala, El Salvador, Honduras and Nicaragua. They cling to the train that some call the "Train of Death" and that others simply refer to as "La Bestia" (The Beast).
CNN
