Boston in Transit - The Book Figure 5.99 - Mapping the Molasses Tank and the El, 1917 On a real estate map of the North End, the Atlantic Avenue Elevated, represented by a pair of parallel dashed lines, follows the grand arc of Commercial Street. Tracks of the Union Freight Railroad, represented by dark lines with cross ticks, trace Commercial Street and the el. To the west of “North End Beach” is a waterfront parcel of land with “Boston Elevated Railway Co.” indicated as its owner (top left). On the parcel is a blue circle representing the infamous molasses tank that burst on January 15, 1919.