Flooding on line.
Arriva Trains Wales and Virgin services were hit after floods around Gaerwen which saw a 5mph speed limit put in place from 10.30pm on Thursday night.
Trains between Holyhead and Chester were delayed by around 20 minutes. This was cleared by late morning and services returned to normal.
An Arriva spokesman said: "The driver of the 10.24pm Holyhead to Crewe service yesterday reported water up to the rail head and in places above the rail head.
"Technicians advise that the Down Line is fit for line speed but the Up Line has standing water approximately half an inch above the railhead. As a result, trains can pass at 5mph."