A deal has been reached between Northern and the RMT that will bring to an end a long-running dispute.
The agreement will mean the restoration of between 60 and 80 Sunday services, some of which have not run for up to two years, the company said.
The dispute centred around working arrangements for staff and regularly led to services being cancelled over the last nine years.
Northern said the deal was “genuinely groundbreaking”, and the RMT union praised the “resolve of [its] members… having fought for years”.
Northern said the Sunday services would be brought back in gradually, so it could “deliver the changes reliably and sustainably”.
Tricia Williams, managing director of Northern, said: “Bringing an end to the longest-running trade dispute on the railway gives us the opportunity to look forward and, importantly, start delivering the improvements our customers have been waiting for.
“We know how frustrating the lack of Sunday services has been for many communities. We are committed to bringing services back as quickly as we can, taking a phased approach over the coming months and prioritising those routes and journeys where the impact has been greatest.”
RMT general secretary Eddie Dempsey added: “The resolve of our members having fought for years, including multiple days of strike action, the efforts of all involved and the distinct change in direction from this government backing the deal has enabled us to reach this successful conclusion.”
Northern operates about 2,650 services a day, serving more than 500 stations across the North of England.