Speaking in Manchester today, Mr Johnson promised to pay for the trans-Pennine leg of the proposed £39bn Northern Powerhouse Rail project connecting the great cities of the North.
Claiming he wanted to do for the project "what we did with Crossrail in London", the new Prime Minister said he had "tasked officials to accelerate their work on these plans so that we are ready to do a deal in the autumn".
But he warned by Yorkshire's only metro mayor, the Sheffield City Region's Dan Jarvis, that "we now need to see action, not just words" and investment was needed for the whole of the Northern Powerhouse Route.
Proposals for Northern Powerhouse Rail, connecting Liverpool and Hull with Newcastle, Sheffield, Manchester and Leeds, were submitted to government earlier this year and were being reviewed by Department for Transport and Treasury bosses.
But Number 10 has promised to publish detailed plans for the Manchester to Leeds leg this autumn after a review of the controversial HS2 scheme connecting London to Leeds, Manchester and Birmingham.
Northern leaders are expected to be watching closely to see whether the Manchester-Leeds leg of Northern Powerhouse Rail comes at the expense of the later stage of HS2, which would connect Leeds to the capital by 2033.
Judith Blake, Labour leader of Leeds City Council and West Yorkshire Combined Authority transport lead, said: “Northern Powerhouse Rail is key to our vision for a modern, reliable transport network that delivers faster journey times, additional capacity and greater reliability and I hope the Government will now work with us to accelerate delivery of this project.
“By integrating Northern Powerhouse Rail, HS2 and an upgraded trans-Pennine line at a transformed Leeds Station we can maximise the positive impact of these investments for the benefit of all our communities.”
Reacting on Twitter, Mark Lynam, the Director of Transport, Infrastructure & Housing at the Sheffield City Region, wrote: "Positive investment in northern transport, but it would be myopic to focus solely on the Leeds-Manchester link. Northern Powerhouse Rail project is a network."
He added that the Power Up The North campaign launched by The Yorkshire Post and other northern titles "only works if a network putting ten million people within an hour of each other is fully built."
Henri Murison, Director of the Northern Powerhouse Partnership representing civic and business leaders, said: ”This is a seminal moment for the North – the entire Northern Powerhouse concept is all about connecting the cities and towns of the North to boost productivity.
"Northern Powerhouse Partnership has been making a strong case for rebalancing our economy and it is heartening to see the first major policy announcement by the new Prime Minister is to benefit the North – matching the commitment of businesses already investing here.
“As well as faster journey times, enhanced capacity and greater frequency, the whole Northern Powerhouse Rail as a network will provide opportunities for our young people to secure the skilled jobs we need to drive productivity and link up the great cities of the North to stimulate economic growth.
"A key part of one of the new lines we need is from Manchester to Bradford through to Leeds, which will benefit those in Liverpool and to Manchester Airport when those sections are also built as well as upgrades so trains can travel on from Leeds to Darlington and Newcastle, as well as wider improvements to for instance get to Sheffield by different routes.”
Conservative Leeds city councillor Matthew Robinson wrote on Twitter: "This is great news for the North. Learn the lessons from HS2 = remain in budget & deal with the route/line. Both are major criticisms of HS2."
Rachael Maskell, York Central MP and shadow transport minister, said: "It's quite embarrassing the Prime Minister had to ask people to applaud his announcement of a faster line between Leeds and Manchester.
“It's quite clear the northern audience know that it's not even a half measure and not worth clapping. Council leaders, Mayors, businesses and Transport for the North all want Labour's Crossrail for the North from Liverpool to Hull and up to the North East, as we promised in our last manifesto, to truly unleash the economic potential of the North.
“This is sadly once again another Tory Prime Minister coming to the North with nothing new. There is no timeline, no linking of northern towns, just more vague promise of a skeleton line, and a rehash of the insulting level of investment for the region that Theresa May tried and failed to bribe Labour MPs with a few months ago.
“Instead of backing Labour’s Crossrail for the North, Johnson is offering a cheapskate refurb of existing lines. There is no timeline on delivery.
“Labour will bring proper investment to the north, prioritising connectivity for rail across the North and putting in vital infrastructure to attract the economic investment for northern towns and cities. A properly integrated rail system can only be delivered under Labour’s publicly owned rail service not the fragmented system this government backs.
“Boris Johnson failed to answer key questions today such as whether he’ll reverse the decision not to electrify the Trans Pennine Rail line and whether it will be upgraded for freight.
“Boris Johnson is pretending he’s interested in the North after decades of Tory neglect, but sadly, this speech shows that nothing has changed once again."
Susan Hinchcliffe, Chair of the West Yorkshire Combined Authority and Leader of Bradford Council, said: “I am pleased that Northern Powerhouse Rail has been identified as a priority by the new Prime Minister and we now need to see the detail of how the commitments made today will be taken forward.
“A new line through Bradford city centre is the best solution for our city, our region and the North of England and we are ready to work with the Government to deliver it as quickly as possible.”
Dan Jarvis, Mayor of the Sheffield City Region, said: “It’s good to see the new Prime Minister in the North. I welcome his commitment to deliver Northern Powerhouse Rail, more powers for Metro Mayors offering real devolution for our communities, providing better bus services and committing greater funds for the Stronger Towns Fund.
“What the North really needs is a sustained programme of investment to level regional inequalities and unlock our huge potential. Good transport infrastructure is key, so today’s commitment to deliver Northern Powerhouse Rail is a welcome first step.
But we need investment to deliver the whole of the Northern Powerhouse route and Sheffield City Region's Integrated Rail Plan. This plan details a vision for the future of our rail services which will transform rail travel for our communities.
“We now need to see action, not just words. I will doing what I can and will be working closely with fellow leaders in the North and with the Prime Minister and his Cabinet team to ensure we deliver for the North.”