This former Union Railway substation once supplied power, I would assume, to the company's nearby streetcar line on Webster Avenue. Union Railway was formed in 1892 to electrify the rail lines of the old Huckleberry Road and replace its horse-drawn cars with trolleys.
How did the Huckleberry Road get its moniker? From Harry T. Cook's The Borough of the Bronx:
One of the curiosities of Morrisania was the "Huckleberry Road" with its bob-tail cars. Old residents never tire of relating some of the peculiar experiences they went thru when this ancient horse-car line was in operation. It is said that whenever the driver hit up the horses to urge them on to greater speed, the car would jump the track; whereupon the conductor would request the gentlemen to alight and help lift the car back upon the tracks. The stoppages were so frequent that the passengers found ample time to pick huckleberries along the road."Hitching" on trolleys was apparently a favorite pastime for many Bronx youths, who would catch free rides by hanging on to the outside of the cars as they made their way down the street. One erstwhile hitcher recalls:
Anxious fingers of unaware hitchers were often smashed by a conductor when the trolley was stopped at a red light. He'd wend his way through a carload of passengers sneaking toward the back to attack unsuspecting hitchers with a wooden club cracking as many fingers and knuckles as possible while condemning the violators to a life in Hell.
