Changes

* Go to "El trebol" (big junction near "La Marin" in the center, final station of the Ecovia-bus). From there catch a bus in direction Tumbillo/Machachi and get out in Tumbillo (~$0,50). There is a gas station nearby.

The turnstiles at the exits of the stations for the rapid transit buses seem to often not lock (maybe the couple I tried were just broken) so you can just walk in the exit. There do not appear to be ticket controls on the buses.