The Oxfordshire Guardian revealed last week a deal had been struck to keep the major Wantage Road route open.
Residents feared traffic mayhem for six months after Network Rail voiced plans to close the road while they raised the height of the bridge by The Volunteer pub.
But last week it was confirmed with Oxfordshire County Council a new bridge will be built off-site instead.
The A338 will still close to traffic for a shorter period whilst the new bridge is lowered into place – but the date and length of closure has not been announced.
The rail company announced yesterday work will start in November and finish in summer 2015.
But two other roads – the A417 Challow Road in Denchworth and the B4017 Steventon High Street – will shut while their bridges are demolished.
The A417 Challow Road bridge will shut from September to December 2014. In Steventon, the B4017 road bridge will close from January 2015 for eight months until August 2015.
Grove resident and parish councillor Frank Parnell said: “It doesn’t sound as if it is quite such the good news we thought – it could cause major problems.
“There will be some issues because a lot of people go from Grove to Hanney along the Steventon High Street to go to Milton Park and Didcot so it will effect all those people.”
Network Rail needs to raise their bridges to install electric wires over the train line below.
The project is part of the £2bn electrification of the Great Western Mainline.
Nigel Fenn, Network Rail senior programme sponsor, said: “This work will deliver quicker journeys for the ever-growing number of passengers on the Great Western line, helping to bring communities closer together and boost the regional economy.
“We thank people in advance for their patience as we continue our plans to build a better railway for the South West and Thames Valley. This is an exciting time for the Great Western as we upgrade and electrify the route to transform our diesel railway into one of the most modern in Europe, providing more seats, even faster journeys and cleaner and quieter trains.”
Oxfordshire County Council is also planning to redevelop the A34 Milton Interchange from autumn 2014 and early 2016, overlapping with the B4017 Steventon High Street work.