Looks like they just placed plastic Safetran 12x24" backgrounds on them... wonder why?
Maybe they somehow thought that the lights had a visibility problem?
Probably had them lyin' around in a storage lot somewhere and Conrail decided that they would be cheaper to put up than getting a can of paint from the store.
Well... whatever the reason, I think it looks ugly!
There are quite a few of those around... especially on the west coast. I don't think that any of those older ones are still in service... at least as a regular school bus though.