United at ORD has a 20 minute check in line. Only pax departing within 20 minutes can use the line and they check bags and more amazingly bags usually make it. And the line is always empty and stocked with 2-3 CSR's. I confess that if I get to ORD with 30 minutes to spare, need to check bags, and if the lines are long or the 1K lines are closed already, I will wait 10 minutes and walk right up to the 20 minute check in line.