On the walls you can read about the progression of chocolate in societies around the world. Aztecs and Mayans were the first to enjoy this plant as a spiced hot drink, though it is not known how the process of picking the plant, then drying, and roasting the beans before crushing them was developed. The Aztecs, among most societies prior to the industrial revolution, valued the cocoa beans very highly, sometimes including them in their blood letting sacrifices. When Europeans discovered the drink the royalty became obsessed and would host chocolate drinking parties where they would sit and drink hot chocolate out of ornately decorated cups. It wasn't until the industrial revolution that chocolate became regularly available to the masses, and it was even later still when Mr. Henri Nestle invented the process for making milk chocolate which is the overwhelmingly favored chocolate in the States!
If you make it to Granada and want to try the Nicaraguan national cocoa drink (Pinol), or if you simply have a few hours to kill here, the ChocoMuseo is a great place to checkout!
The history of this train, as explained on wikipedia, dates back to the 1860's when construction of railways started in Nicaragua (Nica). The overall goal was to connect the Caribbean and Pacific coasts to allow transport of goods through C. and S. America. While the railway did complete several sections between major cities in Nica, the railway cross-country was never completed and in 1914 when the Panama canal was completed, the railway was no longer a viable business option. In 2006 this railway shut-down and now serves as a historic landmark!