The new trains, which will have 330 cargo cars instead of 220 currently, are one of several aspects of Vale's growth strategy to eventually more than double its iron ore shipments out of the Ponta da Madeira port in northern Brazil.
"This is just the first step. We're going to double the size of Carajas," Mauricio Spinelli, Vale's head of logistics, told reporters in Sao Paulo.
Vale, the world's leading producer and exporter of iron ore, hopes to boost its shipping capacity in the region to 230 million tonnes a year by 2012 from 100 million tonnes currently.
The company plans to invest $12 billion in logistics in the next five years as it seeks to keep up with red-hot global demand for minerals and other commodities.