Here is the Bolivian Railways timetable. It's undated so there is no guarantee it's up to date. It shows timetables from La Paz to the Chilean border at Avaroa. http://www.fca.com.bo/Servicios_archivos/P.../itinerario.jpg
This is a wonderful photographic essay of the Uyuni Salt Flats, which you should not miss on your way.http://www.darkroastedblend.com/2006/11/fa...an-salt_27.html
This comment was posted on Trip Advisor in April 2008 by Garth Cape Townhttp://www.tripadvisor.com/members-forums/GarthCapeTownTry Kantuta Tours, firstname.lastname@example.org. I've done the Salar trip 6 times and through trial and error found them to be the best. That said, keep your expectations low. Food is basic, accommodation is basic and flat tyres are very normal. Email them but don't expect a reply. When you get to Uyuni, just go to their office and you can usually arrange for a trip leaving the next day. There is only one way to get from La Paz to Uyuni. Take a bus from La Paz to Oruro and then take a train from Oruro to Uyuni. You will have to leave La Paz at 8am LATEST. You will get to Oruro at about lunch time and the train leaves at 2pm if I remember correctly. If you miss the train, here isn't one until the same time the next day. You arrive in Uyuni at about 11pm so make sure you have your hotel booked. The best hotel in Uyuni is the Tonito Hotel, run by Chris and Suzi, amazing couple and seriously, the best pizza in he Southern Hemisphere, if not the world. Enjoy the trip, it's amazing!
From the Chilean border you must travel by bus, as passenger rail service is no longer operated. It is possible to get to Santiago from Ollague by road. The nearest large city to the border is Calama. Though occasionally there may be through service from Ollague to Santiago, you will probably have to get a local bus to Calama, where there is a regular daily service to Santiago.
Santiago (1,225 kilometers): the trip takes 16 hours average. Several transport companies cover this itinerary with comfortable sleeper and standard reclining seat services. You may access them at:
* Tur Bus
(I can't seem to enter the Pullman Bus site without a Chilean ID. You may have better luck)
There is nothing of much interest to see between the border and Santiago, with the exception of San Pedro de Atacama. http://en.wikipedia.org/wiki/San_Pedro_de_Atacama
Hope this helps a little.