New Braunfels police received a 911 emergency call Tuesday morning from one of the people who were hidden on the train. The communications coordinator David Ferguson , said police contacted the company Union Pacific, which owns the station, and the convoy of 80 cars was arrested.
Police said men from Mexico apparently they slipped aboard in Laredo, about 300 kilometers (185 miles) from New Braunfels, and were headed to Austin.
Forecasters say temperatures exceeded 27 degrees Celsius (80 degrees Fahrenheit) when immigrants were rescued.
Emergency personnel examined all men and several were treated for dehydration.
The 10 men are held at the Department of Homeland Security of the United States. Their names and further details on his condition were not released immediately.