(a) General rule.--Any ordinance widening or straightening any street shall fix the new line or lines. (b) Conformation to new lines.--The ordinance may require that no owner or builder shall erect any new building or rebuild or alter the front of any building already erected without making it conform to the new lines. (c) Right of action.--A landowner's right of action shall accrue only when the city actually enters on and occupies the land within the lines or the building is located or relocated to conform to the lines.
Pennsylvania Legal Code