Cast-iron columns, no matter how historic and pretty they might be, are generally suspect. If the load on them increases, or if any combination of pattern live loading or lateral loading causes bending, they have to be carefully examined for safety in a way that’s not true of wrought iron or steel columns.
The column above, in the 125th Street station on the 2 train, shows an exception. Cast-iron columns were used in stations of the original IRT system, built between 1900 and 1908 (including the early extensions to the system). You can see here that the columns between the tracks, which are potentially exposed to impact loading, are steel, as were the station columns of parts of the system built after 1910.
This column’s gravity loading is heavily dominated by the dead load of earth above, with the traffic live load as a small percentage of the total. And because it’s part of a buried structure, there’s no lateral load to cause bending. This is as safe a place as is possible for cast iron to be.
