The drivers' union, Aslef, claims management at First North Western has introduced unacceptable conditions as part of a pay deal, including drivers picking up litter at stations.
First North Western accused Aslef of reneging on the deal for a 19% pay rise over three years.
The union had called off the action, but reversed the decision claiming the company had altered the terms of the agreement. Passengers at Manchester's Piccadilly station faced long delays as coaches were brought in to replace train services.
Some people said they thought the strikes were stupid, while others had sympathy for the drivers.
Angela Quinn, 38, from Droylsden, Greater Manchester, was travelling to Blackpool with her two young sons. "It is not so fair, is it?" she said.
"Today we were taking the children out of the area, but because they are striking we have to go by coach. The boys were really looking forward to the train."
Charles Essiam, 22, from Sale, was travelling to Edinburgh. He described the strike as "just ridiculous". Further strikes are planned for August 27 and 28 and September 10 and 11.
