IRT on TOP
In the family of PSC covers sometimes IRT comes out on top. This one is from a whole passel of covers along 53rd St in Manhattan between 6th and 8th Avenues.
A grid of small square with some larger blocks for ventilation holes. IRT and PSC are separated by a full bar across.
This is the only instance I have recorded, although I suspect there are other examples along the routes of the IRT.