The so-called Metro del Vallès are actually two Ferrocarrils de La Generalitat de Catalunya lines that run from Plaça de Catalunya in Barcelona to Terrassa and Sabadell respectively.
The two lines follow the same route from Barcelona to Sant Cugat when trains are extremely frequent.
The two lines then separate trains and on the Terrassa line S5 trains only go as far as Rubí whereas S1 trains go all the way to Terrassa Nacions Unides.
On the Sabadell line, S55 trains only go as far as the Universitat Autònoma and S2 trains go Sabadell Ca N'Orlac.
For trains to Rubí and the Universitat Autònoma you have to wait between 65 and 8 minutes and for Terrassa and Sabadell, trains come every 12 to 15 minutes.