The clearance time depends on how many other people are in line - it's quick for you but it depends on how many other flights have come in and from where. The bus-train combination is very slow - about an hour as I recall and not a common thing for those who are not airport employees. The airport is not far from the city so a quick cab ride. There is no shuttle "Calgary Airport Taxi Service is available 24 hours a day. The taxi cost to downtown ranges from $30 to $45 plus airport fees depending on the routing and time of day. All Calgary Taxis are license to serve the airport." The quote, from this site:
http://airportshuttleexpress.com/airporter.htm
has all the information.