Rainbows in the Lehigh Valley Gorge

[TMo]

looking good - am I right in thinking the grain hopper covers are round/square to tell yard crews as for mineral ore's or grain for food ?

Good question!  I know that switching between commodities was discouraged with covered hoppers - they'd have to be cleaned in a lot of cases before a switch could happen.  I've heard that Conrail was not a big fan of bulk commodity movements since these freight shipments weren't the most profitable, and maybe that's in large part to the cleaning requirements. My personal experience with these was driving past quite a few at the concrete plants near my mom's house in Northampton, PA.  All of them tend to be short 2-bay (probably because of the density of what they haul), and they all tend to be "well-weathered" after experiencing concrete dust and the corrosive nitrates in the limestone.