While Lisbon has six tram lines, line 28E (E for elétrico) has the most spectacular route through the hilly historical neighbourhoods, with classic rolling stock. Four other of those six lines also use classic rolling stock and might be seen as no less spectacular; they are certainly less crowded than 28E, as they are not as heavily promoted as 28E is.
Tram 28 runs between Martim Moniz and Campo de Ourique (Prazeres Cemitery). Many visitors ride the tram as an attraction in its own right, and the waiting line is usually long. Try to ride early in the day, or in the evening, or chose instead 12E or 25E (partly on the same route as 28E), or 24E (reopened in 2018 after being valued for 23 years), or 18E (which risks closing due to smaller ridership). The latter two connect to historical neighbourhoods which are usually less crowded with tourists than the usual spots.
The tram is part of Lisbon’s regular ticket system. Period tickets are valid. One-way tickets are sold at the end station. Another option is to walk along the line.
The line is infamous for pickpockets, especially at stations. Watch your belongings. The grades are steep, so standing is difficult.
Citizens in Lisbon use the yellow trams for commuting. Green and red trams are reserved for tourism use.