The final route for HS2's second phase from Birmingham to Manchester and Leeds has been revealed by the Government.
Opponents of the high-speed railway project claim it will run over budget, create havoc during construction and have disastrous environmental consequences.
But supporters hope it will reduce the need for environmentally-damaging domestic flights between London and northern cities.
Where will it go?
The eastern section of the line will link Birmingham and Leeds via Sheffield.
The western branch will connect the West Midlands with Manchester via Crewe.
Will homes be demolished?
More than a dozen new homes in South Yorkshire will need to be demolished to make way for the new railway line.
The eastern section of the line will go through a newly-built housing estate, requiring sixteen properties in the Shimmer estate in Mexborough to be bulldozed.
Residents will lose their homes because ministers decided the line should serve the existing Sheffield city centre station after proposals to run trains to Meadowhall shopping centre were shelved.
Labour's Rotherham MP Sarah Champion said she was "furious" because South Yorkshire "won't get a proper stop".
How much will it cost?
Rail expert Michael Byng has estimated that HS2 will cost more than £400m per mile making it the world's most expensive railway, according to The Sunday Times.
The newspaper reported he calculated the scheme will cost up to £104bn, almost double the Government estimate of £55.7 billion.
But a Department for Transport spokesman (DfT) said: "These claims are incorrect.
"We have not commissioned any advice from Michael Byng on the cost of HS2."
He added: "We are keeping a tough grip on costs and the project is on time and on budget at £55.7bn."
Campaign group Stop HS2 said leaks from inside the project suggested the 351-mile line could end up costing in the region of £200 billion - nearly four times the current £55.7 billion budget.
The Transport Secretary, Chris Grayling, said it was "incredible, inconceivable and simply nonsense" to suggest the cost of HS2 is set to spiral.
When will it be finished?
Preparatory work has begun and major construction projects are due to launch in 2018-19.
High-speed trains are expected to begin operating between London and Birmingham in 2026.
Services on phase 2a from the West Midlands to Crewe are expected to begin in 2027.
Phase 2b from Crewe to Manchester, and Birmingham to the East Midlands and Leeds, is due to open in 2033.
Additional reporting by agencies
