How the railroads were built in Peru is a fascinating story that is tinged with Indiana Jones-like adventure, geographic challenges, dream-obsessed engineers and human drama. I found some interesting resources on the Web:
I've ridden on my share of trains in Peru. In 1971, I took the train to Huancayo. In 1989 and 1990, I was on the Cusco-Puno train several times. And, of course, I went to Machu Picchu a half dozen times. The old site
for the Arequipa-Puno- Cusco service has been replaced by a more polished design and content
because it's being managed by an international consortium now. I suspect there is still a local train for the local residents and backpackers.