The money will go towards works that will deliver trackside upgrades, platform extensions for longer trains and bigger depots across the region.
According to a survey of 5086 passengers from Transport Focus last month, West Midlands Railway was found to have the lowest customer satisfaction rating in the country.
Works are already under way to upgrade trackside equipment between Manchester and Liverpool and platform extensions on the Cumbrian route. This will support the introduction of longer trains with extra seats and an upcoming timetable change across the region with hopes that reliability will be improved.
The government has been criticised in the past by peers and MPs for not focusing enough resources on Northern infrastructure and instead favouring rail services in other part of the country, especially the south-east.
Transport secretary Grant Shapps said: “This £84m investment will make trains more reliable for the people of Manchester and beyond...