The benefits are clear: the train is a safe, comfortable and ecological means of travel.
See here suggestions for your outings.
CP Services: Lisbon urban trains
You can see the time that is left by swiping your card across a ticket vending machine or at any Lisbon urban ticket office.
€2 - Return journey price on the Lisbon Sintra, Cascais, Azambuja and Sado lines per person.
Here are just a few suggestions about where you could go: