Catch the Douro Train in Sao Bento Station after you have taken your time to see the beautiful ceramic tiles on the station walls. Ride the train to the end of the line in Pocinho and walk to Taberna da Julia for lunch. Take a taxi or bus to the new Rock Art Museum (www.arte-coa.pt) in Foz Coa. Going to the Museum by taxi could be costly but it avoids a 3 hour drive from Porto. An alternative would be to get off the train at the next to the last stop (Freixo) and have a wonderful lunch at Bago D'Ouro. In either case, you later take the train back to Porto. this make for a great day.
The train line that runs from Porto to Pocinho deep in the Portugal's hinterland is considered one of the most beautiful in the world. About 60km outside of Porto the line joins up with the Douro and follows its snaking path for another hundred kilometers or so, criss crossing via bridges all the way. The line itself is run by the Portuguese national railway, and the trains are old but not historic. The carriage I sat in, pictured, looked straight out of the 1940s, though, but the engine that pulled it was a fairly modern diesel.
Upstream, however, there are two historic and similarly stunning railway lines that you can detour to, beginning at Peso de Regua and Tua.
Catch a train from either Sao Bento station (central station) or Campanha station (5 minutes train from Sao Bento) and buy a day return ticket to Regua, or Pinhao or where ever you feel like stopping ! The trip to Pinhao takes about 2.5 hours. The interest of this trip is essentially to watch the views from the train on the Douro river and the surrounding vineyards (the nice views only start about 1 hour after leaving Porto though). Not much to do in Pinhao but having a nice lunch and drinking some wine .. waiting for the train back to Porto
Circular tour by train and bus. (Sao Bento station.)
1. Train to Amarante changing at Livraçao.(Photo-Amarante)
2. Bus to Vila Real
3. Train to Peso da Régua
4. Train to Porto
This gives beautiful views of the countryside and of the Douro in particular. May need a taxi in Vila Real - check times before going.
Both the branch lines and the main Douro line are immensely scenic. Amarante is a beautiful town and you can eat a picnic by the river.