I agree with pedmar, the neighbourhood is right and safe. I would say
very well located.
About the second part of your question, UC3M actually has 3 different campuses in 3 different villages near Madrid (Getafe, Leganes and Colmenarejo). If she was told to go by train, then it has to be in Getafe or Leganes (no train service to Colmenarejo). In both cases is a short trip, 13 min to Getafe's campus and 18 min to Leganes'.
This is the 'transportation' page of the UC3M Official site:
http://www.uc3m.es/uc3m/gral/IG/TRANSPORTE/indice.html It is in Spanish only, but surely it will be useful for your daughter.