What does "H/C" as in :Roundhouse H/C Plug Door Boxcar" Mean?

This has me scratching my head: I have a Roundhouse H/C Plug door boxcar for WP. Does anyone know what the H/C stands for?

perhaps “high cube”?

at least that’s the first thing that comes to mind…

Yep, Sister company Athearn uses HC to signify High Cube. They just mean the boxcars are taller than standard

Thanks. These are tall cars.