Hundreds of migrants arrive aboard a cargo train in Ciudad Juarez, on Mexico's border with the United States, risking serious injury or death from accidents such as falling off the roof. "People fainted, Haitians who were with their children fainted from dehydration and no one came to help them," says one Ecuadorian migrant. The aid group Doctors Without Borders (MSF) says it treated more than 67,000 migrants in Costa Rica, Honduras, Guatemala and Mexico last year - a 21 percent increase over the previous year. IMAGES AND SOUNDBITES