Near Chuspipata, the Jungle Rail Trail is an extreme 35 mile route combinig single and double track winding through dense vegetation in the cloud forest. To reach the trailhead, take a minibus from Villa Fatima to Chuspipata.
The track often seemingly vanishes completely as the vegetation closes in, pushing mountain bike riders off their bikes and making for extremely challenging going. Not to mention numerous rock and tree falls which have to be climbed. At the pass, the trail opens out a little into double track plunging rapidly down into the Yungas. This fast three hour descent more than makes up for the first four hours of suffering!!
While on adventure in Bolivia, it is important to keep in mind your own personal safety. Keep an eye out for pickpockets and be aware that it wouldn't be uncommon to have a theft in your room while you are sleeping. This is especially important since the passport/visa replacement process is complex, lengthy and costly.
Overall, Jungle Rail Trail is the 2nd most popular mountain bike trail of all 3 mountain biking rides in Bolivia.