I am taking a bus from Pamplona to Zaragoza. I am planning to roam around for a few hours and then take a train to Barcelona. Is the Alsa bus station in Zaragoza close to the city center - if not, is there any public transport from bus station to the city center? Also, is there a left luggage or locker facility in the bus station or train station? I am told the bus & train stations are very closeby. Am I correct? Would greatly appreciate any inputs.