The Es here stand for Eisenbahn (Railroad). Project Riese was Project Giant. The train ran from Breslau to Waldenburg. It disappeared in the Owl Mountains. There are many legends about the Nazi Gold Train, but the most logical is that they cut a separate line for it, encased it in concrete, and sealed the entrances or collapsed a series of underground tunnels. I believe it exists because it was witnessed leaving Breslau in January 1945. Nobody knows for sure where it went, but that gold, art, and jewels (possibly secret weapons files too) have never reappeared. Reise was a planned underground factory complex with 7 tunnels. Only a few were used and construction kept going. I am only aware of Espenlaub moved there which repaired captured Allied aircraft for KG 200 secret LW missions. They worked on components for fighters and DC transport aircraft. Maybe some of the loot went by air... I really don't know.