The first theft happened on June 1 at Ilkley station when three men stole four bicycles from the cycle rack.
They then boarded a train to Leeds and stole a fourth bike at Leeds station.
Four days later at Leeds station, two men approached the bike rack and tampered with locks on two bikes before stealing them
Officers believe the men shown in the CCTV images may have information which could help them investigate.
Anyone with information is asked to contact Brirish Transport Police by sending a text to 61016. Or call 0800 40 50 40 quoting reference 178 of 15/06/2018.
Or call Crimestoppers anonymously on 0800 555 111.