The deep-jungle city of Iquitos, capital of the Loreto region, is currently accessible only by airplane and riverboat. Recently, however, the regional president of Loreto, Iván Vásquez Valera, has announced plans to build a railroad linking Iquitos with the town of Yurimaguas, located a few hours by road from Tarapoto in the San Martin region of Peru.
According to the regional president, the documentation and environmental impact analysis for the proposed project will be completed in April 2013. Understandably, the project has already raised concerns regarding the potential for environmental damage.
The train line, which would run for an estimated 358 miles (576 km), would pass through swathes of jungle as it makes its way from Yurimaguas and on to Nauta before arriving in Iquitos. Whether the project will become a reality remains to be seen, but the surrounding debate is sure to grow as -- or if -- the proposal gains ground.
For more details of the project (in Spanish but with various maps), see the Ferrocarril Interoceanico Norte document produced by Loreto's regional government.