Consider the P&LE panel side hopper by Accurail.   Along with other railroads, P&LE applied Youngstown aftermarket side panels in the 1930's to their USRA-style twin ribbed hoppers.  Due to corrosion, up to 30 lbs. a month for even the corrosion resistant copper bearing steel, hoppers needed new sides and slope sheets every 10-12 years.

link:  http://www.whistle-stop.com/accurail-ho-p-le-55-ton-panel-side-twin-hopper-2817.html

Accurail has a rather mixed track record with lettering accuracy.  I would invite additional scrutiny and clarifications from list members.

I had looked into these because I model Pittsburgh in 1964-65.  Yet I cannot have one, they were gone by 1962.