Whats the difference between PCR and the SP running scheduled freights before any current mgmt was alive. It seems that way back when frieghts ran as 2nd and 3rd class trains and if needed an extra section or extra train was dispatched.

Given that train sizes and lengths are much longer today, does PSR do the same thing only alowing a more regular train flow that would support crew rest and therefore a safer working environment.

Thanks for any info.