Passengers might remember her better as Mary Dickson, who became the high-profile face of ScotRail once it was taken over by Aberdeen’s FirstGroup in 2004.
She has joined forces again with Dean Finch, the former finance director of First who is now chief executive of National Express.
Mr Finch, once the right-hand man to FirstGroup founder Sir Moir Lockhead, was widely considered to be a strong candidate as his successor.
But when the current chief executive, Tim O’Toole, joined the board of the Aberdeen transport group as a non-executive director, a slow exodus of some of Sir Moir’s key lieutenants ensued.
First’s bus boss Nicola Shaw, now chief executive of High Speed One and who was also considered to be another potential successor to Sir Moir, followed Mr Finch out the door in 2010.
Ms Grant, who eventually took over roles running both the First rail and bus divisions, surprised many when she left without a job to go to in 2011.
But after a short spell of being lavishly entertained by headhunters, Ms Grant emerged in a completely new industry, as chief executive of mobile phone retailer, Phones4u.
It was an invaluable experience, she said, but coming back to her first love is now her priority – and a decision she made in a snap.
“I took a call from Dean who said next time you are in London look me up. I did, and over lunch he said ScotRail is coming up again as a franchise. We did it before as a team. He asked me if I was up for it and I said ‘let me think about it. OK’.”
For many reasons 2014 is set to be a momentous year for Scotland. But added to the sporting events and the referendum, a new operator of Scotland’s rail franchise will also be decided by Transport Scotland.
Ms Grant has been keen to come back despite a successful stint with the phone retailer, which was owned by private equity group BC Partners. Her home and family – and her dogs – are in Scotland. Her commute to the English group’s offices involved leaving her home in Glasgow early Monday morning and returning late on Friday.
But she is convincing when she insists that she is not just taking the job for a the sake of convenience.
“Out of all the jobs I have ever done – I have been in the States, in Australia, I’ve run businesses with 40,000 staff and £2billion in turnover – this business, running ScotRail, is the one thing that has ticked every box for me,” she said. “You’ve got all the conundrums of running a complex logistical business, you’ve got working with people, and you’ve got Scotland.”
Her experience of running a retail operation with 680 high-street stores also adds to her breadth, she said. Because although she has done the job before and then moved onto arguably bigger and better roles since, this time ScotRail will be different.
Transport Scotland has upped the ante for bidders, including a demand for improved passenger comfort on longer routes, including Aberdeen to Inverness.
Other measures in the new franchise include smartcard tickets across the network.
“There’s a real ambition this time,” said Ms Grant.
“What the ministers have said is they are raising the bar, and if you want to be part of that you have to respond well.
“And this is the thing – I do have a USP for delivery. We set a very successful business up but now it needs to move on. It needs to look on to the next 10 years,” she said.
“Ministers want to hand it over to someone they trust can deliver it for them. That is why Dean got in touch with me, because he thought I’m the one who could so this.”
She did not divulge what sort of added extras National Express would bring into their bid to entice Transport Scotland to choose them – the highly competitive process means bidding operators keep aspects of their bid a tightly held secret. But having been on the road surrounded by her devices, she understands the needs of commuters better than many.
“I see digital a very important part of the bid.”
Ms Grant is also unusual in the franchise bid process as not only is she running the bid, but she will also run the franchise.
Final tenders should be in to the government by the end of the month. The award will be made in October with the new franchisee – or the existing owner – taking over officially in April 2015.
The competition is fierce for the Scottish rail franchise. In addition to the incumbent First, rivals vying for the £6billion, 10-year contract include Hong Kong’s MTR, Deutsche Bahn-owned Arriva, and the international arm of the Dutch government rail operator, Abellio.
She said: “If I’m successful in this franchise, I am taking over what I created.”