Thanks to Jimnet2005 Riobamba, Ecuador is getting its first nano-size caches. Recently while sumajhuarmi and I were visiting there we got to look for Riobamba Locomotive #15 (GC2JQQP). This nano is located near the center of town in a small park between two avenues. The cache page gives some of the history of how the railroad was built in Ecuador. Jimnet2005 has added a spoiler to help you find this one. Thankfully I had sumajhuarmi helping me. She made the find!