The incident happened at 10.30am on Friday, September 28, where a man approached two different passengers and stole their bags.
A police spokesman said: "Officers believe the man shown in this CCTV image may have information which could help them investigate."
A spokesman added that he "may be local to Preston" but is believed to have traveled towards Chorley or Bolton.
If you know who he is then contact BTP by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 205 of October 19.
Alternatively ring Crimestoppers anonymously on 0800 555 111.