Bramall joins ATOC in the newly created role of director of public policy.
He reports to director-general George Muir.
The Strategic Rail Authority's abolition later this year is expected to provide ATOC with greater teeth and an easier path to lobby the Department of Transport, and specifically the Secretary of State Alistair Darling.
Bramall said the body was keen to 'develop a position' on government plans to create regional transport boards. It also wants to uphold the interests of train companies on other transport proposals, such as the launch of congestion charge zones in the country's provincial towns and cities, which would have a knock-on effect on train use.
'There's no denying that public funding for transport is tight. Our job is to back the railways' corner in any way we can,' Bramall said.
In addition, ATOC will need to justify increased fares to improve the state of the rail network and get involved in the structuring of rail franchises.
Bramall stepped down as deputy managing director of transport public affairs consultancy The Waterfront Partnership last August after nine years with the company. Prior to that he spent 15 years at the Department of Transport in a variety of policy-related roles.
ATOC announced at the end of last year that travellers made more rail journeys - 1.05 billion - than for 45 years, with the number of trips up four per cent on 2003.
Muir said: 'The winding down of the Strategic Rail Authority means train operating firms will have even greater responsibility for championing passenger interest and planning the railway.' He added that Bramall's appointment would 'sharpen ATOC's policy outlook'.
In addition to Bramall, ATOC has appointed Virgin Trains strategic development director Russ Cunningham as head of railway planning and Chris Queree as head of systems innovation for rail settlement and ticketing systems.