Well, actually the San Diego does not have a bell, but actually a buzzer. Anyway, the San Diego trolley is as much a San Diego landmark as it is a mode of transportation. Though the lines are limited, it does cover the heart of San Diego pretty well, including Ols Town, Mission Valley, SDSU. downtown, and Little Italy, You can also take the trolley down to the US/MEXICO border and then walk across. The trolley cars are well maintained and it's usually not too crowded.