There were severe delays affecting the Bakerloo line on Saturday (December 20) following the incident.
Police were called to the station at 8.28am to reports of the assault.
The man, in his 30s, was arrested in connection.
As of a result, the delays affected stations between Queen’s Park and Harrow & Wealdstone.
There was good service on the rest of the line.
Delays also affected the Lioness line due to the customer incident.
A British Transport Police spokesperson said: “Officers were called to Willesden Junction Overground station at 8.28am on Saturday (20 December) following reports of an assault at the station.
“Officers attended and a man in his 30s was arrested in connection.”
