1 hour 30 minutes. According to Baidu map, the whole journey from Southwest University to Chongqing North Station is 39.3 kilometers, and it takes about 1 hour 10 minute by subway, passing through 16 station, and * * * changes twice.

1. First walk about 440 meters, arrive at Southwest University, take rail transit line 6, pass 12 station, and arrive at Ranjiaba.

2. Then walk about 20 meters to Ranjiaba and take the rail transit loop. After 4 stops, walk about 230 meters to the South Square of Chongqing North Railway Station and reach the destination.