To answer the original question, you can usually use www.flightstats.com - first look at "arrivals" under the airport page, filtered by CO - it shows the gate that each inbound aircraft is scheduled to arrive at. From that, you'll find the inbound flight number, which you can then click on to track.

At hubs there is a chance of this method failing, as CO (or any other airline) has more of an ability to swap out an aircraft at short notice, but the vast majority of the time it works for me.

Unfortunately it doesn't make you any less delayed