When I used to lived in Madrid (1970-1974) I used to go play baseball at the parque de la elipa by bus, the P13. I have been trying for years to find it again, and it was gone.
By chance, finding info on the strike of tomorrow I found it, and led me to this wiki page that explains it all

http://es.wikipedia.org/wiki/L%C3%ADnea_113_(EMT_Madrid)

With all the new changes in Madrid, one has to catch up, and now I realise that they have change all the nomenclature of bus route creating the EMT, and my old P13 is now the 113 lol!!

I am so happy, will need to write more about it. Its been that old ,but good times are never forgotten. Madrid forever!!!