Actually, anything in the dual flags scheme or the golden beaver logo should be Soo Line Red. Hard to believe these units actually started out the same colour, but it's true. I personally find Polly Scale's Soo Line Red to be far too purple, and not vibrant enough. Floquil's Soo Line Red is very close, and Badger's Modelflex Soo Line Red is about the best I've seen. (if only it weren't such horrible paint) Scalecoat's CP Rail bright red is actually much closer to the factory-fresh colour of the "action red" of years gone by.
If you are painting the action red schemes, you can pretty much take your pick of any of the "CP red" varieties. For a newly painted unit, use the Scalecoat CP Rail bright red or Polly Scale SP Scarlet straight from the bottle. Action red fades badly into various shades of orange and/or pink, so for an older unit you can use almost anything. If you were to see a consist of 4 action red units today each one would be a different colour, so accuracy here is very subjective. Pick what looks right to you.
Walkways and underframes on all CPR units are flat black. I use Polly Scale Engine Black, but any flat black will do. Don't forget to add the usual CPR coating of grime; the only clean CP engine is a brand new CP engine.