If built badly, the railway risks breaking through the fragile ground, including into yet-to-be explored caves below, says Emiliano Monroy-Rios, a Mexican geochemist with Northwestern University who has extensively studied the area's caves and cenotes. Diesel, he adds, could also leak into the network of subterranean pools and rivers, the main source of fresh water on the peninsula.
By Cassandra Garrison and Jose Luis Gonzalez MEXICO CITY (Reuters) - Parts of Mexico's remote southern jungles have barely changed since the time of t.