Salt factory steel girder object.

This object scales visually, but the hit box doesn't. I am trying to make a moving wall using the steel girder. I can use multiple small ones, but there is a bug where I can stand on the top edge. There seems to be 2 things that makes this happen:
1) girders are not pixel perfect aligned.
2) girders are moving using way-points even after pixel perfect alignment.

here is a picture, they are pixel perfectly aligned both when stationary and at the end of the way-point.

I'm not sure what I can use now for a 14 block high moving wall.