Northern rail is reinstating 75% of the services it cancelled after a new timetable led to severe disruption.
It scrapped 168 services per day last month to try to relieve chaos caused by the timetable’s introduction in May.
On Monday, services in Manchester, Merseyside and Lancashire are partially resuming while all trains on the Lakes Line, in the Lake District, are being reinstated.
The remaining 25% of its cancelled trains do not restart until September.
The company, which has faced calls for it to be stripped of its franchise, says a “more gradual” reintroduction will ensure a more stable and reliable service.
But Greater Manchester Mayor Andy Burnham has written to the prime minister, asking her to personally intervene over the “chaos” caused by Northern this summer.
“This is no way to run a railway and we cannot continue to put up with a rail service provided when the operators can be bothered,” he wrote.
“People’s lives are being badly affected by this chaos and the government cannot continue to turn a blind eye to the plight of Northern commuters.”
A government spokesman said: “The disruption that Northern passengers have experienced is unacceptable and it is vital that services continue to improve and passengers are compensated fully.”
Thousands of passengers have applied for compensation from Northern, which made the first pay-outs last week.
David Brown, managing director at Northern, said the cancellations since 4 June had been an attempt to alleviate “significant disruption” caused by the nationwide introduction of the new timetable in May.
He added: “Whilst we are ready to reintroduce all 168 daily services, given the need to drive further improvements across Manchester, we have agreed to a more gradual reintroduction of our services.
“A phased introduction is the right approach to ensure a more stable and reliable service for customers.”
In May, what was billed as the biggest ever overhaul of rail timetables led to significant and widespread rail disruption.
The timetable overhaul – for Northern as well as Govia Thameslink Railway (GTR) lines – was aimed at improving punctuality and boosting capacity, but instead led to a huge number of train services being cancelled or severely delayed.
Northern and GTR had to remove hundreds of trains in a temporary timetable change to deal with the chaos on the rail network.
Last month, Transport Secretary Chris Grayling defended his handling of the saga and announced an inquiry into what went wrong.
The inquiry, by transport professor Stephen Glaister, will look at the implementation of the new timetable. A final report will be published by December.
The Transport Select Committee is also asking for evidence from passengers and as well as rail industry groups.
Train timetables are usually changed twice a year, in summer and winter, but normally on a much smaller scale.
A rail timetable overhaul planned for December has since been scaled back amid fears of a repeat of the chaos seen in May.
Services to be reintroduced on Monday:
- Lakes Line: All services
- Blackpool: All services from Blackpool to Manchester Airport and Manchester Piccadilly
- Blackpool: Seventeen services a day, out of 30, between Blackpool South and Colne, via Preston
- Lancashire: Ten daily services, out of 16, between Ormskirk and Preston
- Lancashire: All 24 services on the Lancaster to Morecambe line
- Lancashire: All four services between Preston and Blackburn
- Manchester: Four services a day, of 10 removed, from Kirkby to Manchester Victoria via Wigan
Services to be reintroduced in September:
- Blackpool: The remaining 13 services between Blackpool South and Colne, via Preston
- Lancashire: The remaining six services between Ormskirk and Preston
- Lancashire: The six Blackburn to Southport services
- Manchester: The remaining six services from Kirkby to Manchester Victoria via Wigan
- Manchester: The 12 Manchester Victoria to Stalybridge services