To the north of this section, from 125th Street to 130th Street at the Harlem River, the line was constructed below grade. Arched brick tunnels were built wherever sufficient room allowed for it. Beam tunnels were constructed where the headway was too small for an arched tunnel, and where room did not allow for that, open cuts were constructed. The rock tunnels were built between 92nd Street and the north side of 94th Street. Between 48th Street and 56th Street, the line was placed into a shallow open cut. To allow people and vehicles to cross over the rail line, eight pedestrian bridges were built over the line between 45th Street and 56th Street, and vehicular overpasses were built at 45th Street and 48th Street. To cover the frequent openings between 50th Street and 96th Street for ventilation, the roadway's center was landscaped and fenced off. These malls were narrowed significantly in the early 1930s to accommodate additional lanes of traffic. These malls and the street's great width distinguish the street above, and contribute to Park Avenue's identity as a sought-after residential address.