There were indeed back doors to these rowhouses. However, you couldn't get to the street from the back yard unless you went through the house so they would put in these passageways so that the back yards would have access to the streets without having to go through someones house. Most of the backyard gardens (as they used to call them) had a gate which opened onto a common path which led to the passageway. Not a lot of privacy in the back from your immediate neighbors.