The first seven-days a week service on the Maryhill line from Queen Street to Anniesland began running this week.
Ten trains each Sunday, starting at 9.26am from Queen Street and terminating at Anniesland, were in operation, with trains running hourly until 6.26pm.
The trains serve six stations on the line; Ashfield, Possilpark and Parkhouse, Gilshochill, Summerston, Maryhill and Kelvindale.
The line ends at Anniesland, but passengers can connect with trains heading to Balloch and Helensburgh as well as into Glasgow Central or Queen Street via Partick.
Local politicians who had campaigned for increased services on the line used trains on the first Sunday.
A threat to the line's future was ended when Deputy First Minister Nicola Sturgeon intervened to say no SNP Government would allow it to close.
Patricia Ferguson, Maryhill and Springburn Labour MSP, backed calls to ensure the stations remained open when there was a threat of closure.
She said: "It was great to see so many local people using the new Sunday service on the Anniesland to Queen Street line.
"If passenger numbers on the first day are anything to go by this new addition to our train service will be a real success."
Bob Doris Glasgow SNP MSP, who had called for a seven-day service, tweeted a picture of the timetable and said: "I'm delighted to use the new Maryhill Sunday service.
"It is good to see it starting."
Previously, Sunday services had only run in the weeks leading up to Christmas for shoppers.
First ScotRail introduced the permanent Sunday service because it believed there was demand form people in the communities along the route