The plans would slash train journey times from Berkshire stations to Heathrow Airport and could be in place by 2021.
The WRaTH stakeholder steering group met on Monday (7) and Malcolm Parsons, Network Rail’s senior programme development manager, said: “This wil mark a significant milestone to the scheme, taking us one more step closer to achieving the aspiration of delivering this major rail upgrade.”
The group also approved plans to re-establish a public interest group (PIG) as part of a wider communications and engagement process to keep people up to date.
Ruth Bagley, chair of the steering group and lead for Thames Valley Berkshire Local Enterprise Partnership, said: “Identifying a single option will mark a considerable step forward for our plans to improve rail access to Heathrow from the west.”
She added: “What has marked this project out is the coming together of stakeholders around a preferred route which will be in the best interests of the largest number of passengers.
“Once the single option is published, minds can be focused on the more technical stages of delivery.”
The next step would be to get a development consent order, which needs ministerial approval to proceed. This stage could be concluded towards the end of 2015.
The proposed rail link would directly serve Slough with four trains every hour - slashing travel times from 45 to six minutes.