Just noticed that the yards that were always busy in Altoona, PA are torn out. It's the large yard that was under the 8th St bridge. I'm assuming it was NS that tore it out as the arials still show it in place and jammed with boxcars in 2010 but by 2013 it's all gone. Today just grassy fields. Why were the yards removed?
Changes in operational practices, that's all. Of course, having cars arriving from or going to numerous branches (now gone) didn't help either - these cars no longer needed to be sorted out and blocked.
The vast majority of cars going through Altoona have already been pre-blocked either in Harrisburg or Pittsburgh and pass straight through Altoona without needing to be further sorted out.