Although parts of the Portuguese rail network are reasonably efficient, particularly between the major centres, trains on some regional routes can be excruciatingly slow.
Many trains require a supplement.
The fastest of those that don't require a supplement are called Inter-Regional. You can also ride the much slower Regional trains without paying a supplement. This travel pass is valid for four days of 1st class travel within a 15 day period. This travel pass is good for unlimited travel during the validity of the ticket. A supplement is payable on trains with compulsory reservation.