The minister in charge of the East West Rail project says there is a “very powerful” argument for it to go via Cambourne.
On a visit to the Queen Edith's ward to support the Conservatives' South Cambridgeshire candidate Anthony Browne, George Freeman said a decision on East West Rail "will be one of the first things we do if returned to office".
He also said "the southern route for me has a lot of environmental impact".
Mr Browne said: "I have been talking to him about transport issues facing South Cambridgeshire.
"He's responsible for East West Rail and I have been making the case that the line should go north, with a station at Cambourne, rather than south with a station at Bassingbourn."
He said he was "confident" his case is being heard by senior Conservatives.
Labour candidate Dan Greef said "I think we have full consensus between all parties that this [a northern route via Cambourne] is the best option," but said he wants to see greater investment in the bus service in the meantime.
Liberal Democrat Ian Sollom said he and his party has been arguing for a northern route via a Cambourne station, and said the "the signs are very good" that their points have been heard.
But he said it was "disappointing" there were no plans for an electric line to reduce emissions.
Mr Freeman is contesting the Mid Norfolk constituency.
Mr Freeman said: "As a minister of the crown, during an election I'm bound by purdah and I can't make any announcements, and I can't announce any decisions, which for the record have not yet been taken - it will be one of the first things we do if returned to office.
"But I have been consulting widely with the East West Rail Company that we have set up, with councillors, with local MPs and mayor Palmer and the mayor of Bedford, and essentially the real option is do we come in from the north, via Cambourne, or south via Sandy-Bassingbourn, to Cambridge South Station.
"Having grown up here, having lived here, having worked in the biomedical campus, having worked at Babraham, having been the minister for life sciences, it's quite clear to me that station location is obvious.
"It's at the biomedical campus, and the argument that Anthony [Browne] has been making today and that others have made for coming in from the north are very powerful.
"Cambourne wants a station, wants to grow, wants to improve its connectivity and through-fall, and the southern route for me has a lot of environmental impact around Sandy and Bassingbourn and Wimpole."
Asked if the building and running of East West Rail would be carbon neutral he said "I have not set a target on that yet".
And he added "I wouldn't want at this stage to commit any section of track, or part of it [to net zero carbon]".
He also gave an explanation for "downgrading" the expressway between Oxfordshire and Milton Keynes, saying if re-elected he will be "pushing" for the rail link between Oxford and Cambridge.
But said the decision to review the expressway would not affect road upgrades in Cambridgeshire.
He said he has announced the department for transport will release a decarbonisation plan which will "show how we are going to do the modal shift, get people into electric cars and lead the world."
He added: "And as part of my work on east-west, that's why I have announced the review to look again at the expressway.
"It seems to me that if we are really committed to fast rail, clean smart transport, the priority is the rail link.
"And if I'm returned to office after the election I will be pushing to do the rail link into Cambridge, so that Cambridge and Oxford is properly linked by fast regular rail, and downgrading the expressway on the Oxfordshire end, where we need important local links to the M40 and to the ring road, but I don't think a motorway through Oxfordshire is what should be our priority.
"I have announced the review and am proposing to pause on that [the Oxford end] and focus on the rail link.
"Here in Cambridgeshire there is some really important local road works that need to be done in order to develop a more coherent and better transport system."