Train operator Avanti West Coast is to increase its services after slashing timetables more than five weeks ago.
The company said it will run extra trains on its key London-Manchester and London-Birmingham routes from Tuesday September 27.
Services will be boosted again in December once new drivers complete training.
Avanti West Coast reduced its timetable from seven trains per hour to just four per hour from August 14.
This was aimed at cutting short-notice cancellations after a sharp decline in the number of drivers voluntarily working on rest days for extra pay.
The company is one of many train operators engaged in an industrial dispute with its workers.
Avanti West Coast will initially run an additional 10 daily trains between London Euston and Manchester Piccadilly on Tuesdays, Thursdays and Sundays, and an extra six on Wednesdays.
An extra four daily services will operate between London Euston and Birmingham New Street on Tuesdays, Wednesdays, Thursdays and Sundays.
Timetables on the remaining days will be boosted “as soon as possible”, the company said.
The further increase to services in December will see a return of three trains an hour between London and Manchester, an extra hourly train between London and Birmingham, and the restoration of direct trains to North Wales.
Avanti West Coast said it carried out “intensive analysis” of the number of additional trains it can run “in a reliable and sustainable fashion” without relying on overtime working.
It expects nearly 100 new drivers will be cleared to take control of passenger services between April and December.
Office of Rail and Road figures analysed by the PA news agency show Avanti West Coast was the worst-performing operator for reliability between July 24 to August 20.
It had its highest ever cancellations score for a four-week period of 14.9%.
Phil Whittingham stepped down from his role as managing director last week.
There have been calls for the operation of Avanti West Coast’s services to be taken into public ownership since it cut its timetable.
Greater Manchester mayor Andy Burnham insisted “major change is needed”.
Avanti West Coast’s executive director of operations and safety Barry Milsom said: “We know we’re not delivering the service our customers rightly expect and we apologise for the enormous frustration and inconvenience this is causing.
“The decision to reduce our timetable in August was not taken lightly but our customers and communities deserve a dependable train service, so we’ve been working hard to rebuild our timetable in a resilient and sustainable way.
“Resolving this situation required a robust plan that allows us to gradually increase services without being reliant on traincrew overtime.
“We are now in a position to start delivering this incremental increase in services, followed by a further increase in December.
“We’ll continue to review our timetable beyond December with our industry partners.
“We’re working with our people, their union representatives, and industry partners to match the resources we have to demand, so we can deliver reliable services across our network to all our customers and communities.
“We would like to thank our customers for their patience and understanding during this period.”