Previous: Introduction to scanners | Programming scanners
Now that you have an idea how to program a scanner, what do you put in it? You need to know the frequencies you want to monitor. For Canadian railroads, your best bet by far is to get the Canadian Trackside Guide, the railfan's "Bible". You can buy it direct from the Bytown Railway Society, at your local hobby store, or try to find it on Amazon. The price ranges from $28 to $33. You can always buy a used one for a little less money, since the information inside does not change that much every year.
You will need to go to the list of subdivisions for the railway and location(s) you are looking for. For example, suppose you want to know the frequencies for CN trains in Portage la Prairie, Manitoba. You would go to the CN subdivision section, then find out what subdivision Portage is on (CN Rivers). Then find the frequencies listed for that subdivision.
There is typically one train channel for the entire subdivision. In fact, for CN it is the same frequency for every subdivision. This channel is used for trains to talk to each other. They are often used to announce signals as they approach them ("VIA 1 clear signal at East Tower") to alert other trains and crews of their presence.
There are one or more RTC channels per subdivision. These are used to call the RTC (Rail Traffic Controller) to get permission to occupy track, or to do track work. Much of the RTC channel traffic is between maintenace of way (MOW) personnel and the RTC, but the train crews use it on occasion. It is helpful to listen to RTC traffic as you can get clues as to when trains will pass certain points.
Engineering channels are also listed, for use by the MOW crews, but I do not find them to be very useful to listen to.
Load your scanner up with channels for the areas you visit most. I have CN and CP channels in my scanner, on different banks so I only listen to the channels appropriate for the railway I am near.
Next, a few comments about the legalities and ethics of scanner use, followed by some tips and tricks.