First of all this is a great photograph. Now the question is "where was it taken"? It looks like the vehicle in the center was an electrified trolley. Back in the 20's , I know that there were trolleys running on Hudson Street, Main Street and Passaic Street. It looks like the trolley picked up it's power from wires suspended from the power lines running along the Street.
Look at the burning building. Now, without the benefit of having been a firefighter, it appears that the burning floors could be above at least three floors from the bottom of the structure. Look at the water stream at the left of the building, it seems to be concentrating at the top of the bottom three floors. It looks like this building would have been a six or seven story structure. Even though there are one story residential buildings on the right of the building, Hackensack never had high rise residential construction until the 60's.
I would have to guess at this point that unless there was a major industrial or manufacturing building that was six or seven stories in height, and was located along one of the trolley lines, the photo might not have been taken in Hackensack.
Perhaps Irons could shed some light on the photo?