Getting all nodes belonging to a category

Greetings

I’m completely new to Open Street Maps, I reach the site looking for a Transmilenio Map, as you can imagine I’m from Colombia.

Actually I’m working in a Traffic model, basically I need to describe the massive transport system “Transmilenio” here in Bogota, my first step is to get an accurate map of the System (All stations, roads, intersections, connectios, ect.), looking for that I landed in Openstreetmap.org where I found the information but it is fragmentary so I would have to look for every single part of the grid in order to get the whole information. Is there any way that I can search for all nodes who belongs to “Transmilenio”? (They are allready marked individually)

Thanks in advance for your help.

You can use the Overpass query language for that. You can use that language e.g. from http://overpass-turbo.eu/

I have tried http://overpass-turbo.eu/s/lLW and it shows only a handful of bus stops operated by Transmilenio.
You might have to adapt the query in case another tagging scheme is used, or you might have to adapt incorrect tagging to get more bus stops. Of course, it is also possible that the bus stops are not mapped yet.

Please note that there is also a (practically unused) forum for the Colombian community, a mailing list and a facebook group: https://www.facebook.com/groups/OsmCol/

Those are ideal places to get in touch with the local mappers that might help you out with advice and mapping the bus stops.