Air Brakes are a Special Endorsement on you licence.
Various provinces offer free guides online.
Nova Scotia Air Brake Manual (PDF)
Ontario makes it available as a web page Only
http://www.mto.gov.on.ca/english/handbook/airbrake/
Newfoundland
http://www.servicenl.gov.nl.ca/drivers/DriversandVehicles/driverlicensing/airbrake.pdf
New Brunswick
http://www2.gnb.ca/content/dam/gnb/Departments/ps-sp/pdf/Publications/ab_manual-e.pdf
Manitoba
http://digitalcollection.gov.mb.ca/awweb/pdfopener?smd=1&did=20528&md=1
Sask
http://www.sgi.sk.ca/pdf/airbrake_manual.pdf
