At approximately 1830 hours, Box 1-4 sent Squad 8, Wagon 4, Towers 1, 2 to the area of 19th and Regina Streets for a house fire. Responding units were advised of multiple calls prompting the box to be upgraded to a first alarm assignment. Companies arrived with heavy fire on the first floor of an occupied, 3 story, duplex at 1851 Whitehall Street. Crews went in service with a 1 3/4 inch hand line and made an aggressive attack on a fire involving a room on the first floor. The fire was knocked down quickly with negative extension. No injuries were reported and 2 occupants were displaced.