I was assigned a Volvo to replace a Sterling that was being retired. it was the quietest, roomiest, smoothest riding, best maneuvering, ugliest, and worst pulling truck I'd ever driven. The rumor I heard was that the previous owners, Talon Logistics/Giant Eagle, had some sort of removable part, like a computer chip, that was replaced with the factory original when the trucks were traded in. Whatever was done caused these trucks to fall flat on their face at the very sight of a hill. This info came from a Talon driver who I was having trouble keeping up with despite the fact that I was empty and he had 14k lbs of groceries on a reefer. He was in tractor #627 and according to the key chain that came with my tractor, I was in ex-#632. It's a shame because I would've liked to stay in that tractor long term. There are now a few white Volvo single axles with Pitt Ohio logos at the Pittsburgh terminal. My guess is that these were part of a used equipment purchase for Dohrn and they decided to keep a few for city work.
I believe there are only 6 CNG Freightliners, definitely less than 10, and they are based at the Pittsburgh and West Middlesex terminals because they have easier access to filling stations than other terminals.