For more about Asarco Grupo Mexico's railroad, read this

"Out in the West Texas Town of El Paso" from May 16th, 2007, THE TEXAS OBSERVER

"There’s a been a lot of talk of relocating rail lines to Santa Teresa, which would obviously benefit Sanders’ business parks. One 2003 study, which was prepared for the city of El Paso, recommended moving many regional urban rail facilities to Santa Teresa, including the Union Pacific and Burlington Northern Santa Fe’s rail yards in El Paso, as well as the Ferromex rail lines in Juárez.
In addition, Union Pacific Corp’s planning a $150 million terminal just four miles west of Santa Teresa that may process as many as 100,000 container units per year, according to news reports."

http://www.texasobserver.org/blog/index.php?name=out-in-the-west-texas-town-of-el-paso/
[only cached version now works]

ASARCO Grupo Mexico and potential I.P.O. railroad offer

http://www.reuters.com/article/idUSN2318083620100723

July 23,2010:

"Grupo Mexico is also considering spinning off its railroad unit in an initial public offering next year."

[do keyword search in this blog for "Ferromex", or "Railroad" or "Punta Colonet"]