There is a bus in Philadelphia which SEPTA does not talk about. It is not listed on the website. It has neither schedule nor route. It drives the city in a pattern known only to its driver, and perhaps not even to him. Its electronic reader board never displays a number, only “SEPTA.” People who know it call it the Zero, the Random Bus, the Wandering Bus, or just The Bus. It is not a bus for people who know where they want to go. It is a bus for departures.

The Bus has a way of showing up when you are at your lowest. You will hit a certain point, feel a disconcerting crumple in an inner place you thought solid, like a hand crushing an origami box. Just then you look up to see The Bus a block away. You always need to run for it, but just a little bit. Just enough to show you need it. It will wait.

There is an automated voice. It does not say Route forty, service to Second and Lombard. The Bus does not deal in those specifics. It says only Service from and the name of the intersection you are standing at. The doors clunk open, you get on board, the doors hiss shut, and the bus moves on. The driver does not ask where you want to go, but many passengers tell him anyway: Just drive. You pay fare if you can, but if you can’t, the driver will nod, with eyes covered by his blue hat, and you will nod and you will head to your seat.

The shifty and the shameful and the shameless ride Philadelphia’s buses. But most of them are trying to get somewhere. They want to see someone, or acquire something, or get to a place by a time. The Wandering Bus is not for them. Its riders are the people who need to leave wherever they are at that moment. Just leave. The bus goes everywhere. It has been seen in West Powelton, and Grad Hospital, and Center City. It drives down Passyunk, and Haverford, and Dauphin. Most people don’t notice The Bus because it isn’t the one they’re looking for. If your heart is bright and your spirit buoyant, it is likely that you have never seen The Bus.

The Wandering Bus serves a wider clientele than you might think. The failing businessman, the addict’s sister, the questioning Reverend have all ridden on The Bus. Even a mayor and a police chief and a manager of the Phillies. There is no conversation on The Bus. What’s more, when you get off, you cannot recall who was on The Bus with you, or how crowded it was. You remember only that you sat by the window and watched the city slide through your translucent reflection. At some point, you were moved to pull the cord and disembark. One night, your feet hit the pavement, the bus pulled away, and you found yourself near to where you needed to be.

Folks say that some people have ridden The Bus for years on end. Others predict that The Bus will one day leave the city, taking its passengers with it. A woman who knew many things said there was a Wandering Bus in every city she had ever visited. There are even a few who claim that if you ride The Bus long enough, you will one day be dropped off back before your troubles began. But those people are never on The Bus when they say it.