Guidelines for Routine Overhaul (ROH) and Periodic Overhaul (POH) specifically for hopper wagons .

He clutched the satchel to his chest. The knowledge in that book was a map to a hidden world, but it was also a death sentence. As the boots rounded the corner, Elias realized the irony: the pamphlet wasn't about track geometry. It was about keeping things quiet. And tonight, he was the noise they needed to silence.