Politicians and businesses in the Midlands have urged the prime minister to back a £3.5bn plan to overhaul the region’s railways with “long-overdue investment” in better connections between its cities.

Following the success of Transport for the North in securing Boris Johnson’s support for parts of its strategic plan, including significant rail investment, a coalition of local authorities, universities and companies is hoping for a similar endorsement for the Midlands Engine Rail scheme, which would be integrated with HS2 to directly benefit 60 towns and cities in the region.

The plan aims to increase the speed and frequency of existing services such as Birmingham to Nottingham, and also to introduce new direct trains from Coventry and Birmingham International to cities such as Newcastle and Sheffield. Its backers say the 20-year plan would “supercharge” the economy and would reduce carbon emissions by taking millions of passenger and freight journeys off the roads. As a central hub for many journeys, it would also speed up connections across the country, with benefits from Cardiff to Newcastle, they argue.

Sir John Peace, the chair of Midlands Engine Rail, said funding the scheme would be “essential in creating a more sustainable, productive and mobile Midlands”. He said more people than ever were already travelling on the region’s railways, but added: “We now need investment from government to allow our people, businesses and infrastructure to reach their full potential, and to drive a further boost in passenger numbers.”

Midlands Engine Rail, due to be launched at the Bombardier train factory in Derby on Thursday, covers a range of projects, the core of which is a £2bn “rail hub” scheme for infrastructure, including two new viaducts in Birmingham. It would allow 20 extra trains an hour to reach an enhanced Moor Street station, allowing for better connections to services on the HS2 line due at the city’s rebuilt Curzon Street station from 2028.

Another 72 freight trains could also run each day, the equivalent of a million lorries a year.

The creation of new junctions on to HS2 lines could also cut journey times between Birmingham and Nottingham by more than half, the report says.

The future of HS2 remains in doubt, with the Oakervee review due to report in October for the government to make a “go or no-go” decision by the end of the year. The high-speed network is expected to cost £88bn and to be five to seven years behind schedule.