The Funicular dos Guindais is a quick and easy way of getting from the Batalha area (near the Cathedral) at the top of town down to the Ribeira - or more importantly back up the hill. There are plenty of other ways of getting between these two parts of town but it does involve a very large hill.
The funicular was reinstated as recently as 2001, although there was a lift in the same location a century earlier. Apparently that shut down after a serious accident - but don't let that put you off!