Extra train carriages are to be put on as drivers are warned to avoid the Forth Road Bridge this weekend.
The bridge will only be open for local access as work gets under way to demolish the old B800 bridge over the A90 south of Echline junction.
Drivers are being warned to expect “inevitable” disruption as the surrounding road network is closed to all traffic for a huge part of this weekend, next weekend and on November 14.
The A90 and M90 (M9 Spur) will be closed to all traffic south of Echline to north Barnton.
In addition, operators of the Forth Road Bridge are taking the opportunity to undertake essential maintenance and a single lane contraflow will be in operation across the bridge.
From 8pm on Saturday and on October 31 and November 14 the A90 and M90 (M9 Spur) will be closed in both directions through to a latest re-opening time of 6am on the following Monday mornings.
Transport Scotland, Roads and Infrastructure Manager Steven Brown said: “All road users are advised that considerable delays are expected in the vicinity of the Forth during these closures and diversion routes will also be very busy.
@Dawniedee5190 Here is the map showing the closure point,you will not be affected Kirkcaldy to SQ. Have a great day! pic.twitter.com/7rE2inFIX1
— Traffic Scotland (@trafficscotland) October 20, 2015
“Disruption is inevitable in these areas and we would strongly recommend that people should only travel if their journey is absolutely necessary.
“Those travelling to and from Edinburgh airport should also take the closure into consideration when planning their journey.”
Just two weeks ago there was travel chaos when the bridge and A90 had to be closed while experts safely blew up an historic explosive device found on the building site for the new Queensferry Crossing.
Alluding to that, Mr Brown said: “As we’ve seen recently, unexpected closures of the Forth Road Bridge can quickly create problems on the network.
“That’s why we’re doing everything we can to minimise disruption and alert people ahead of time.
“We’ve worked with ScotRail and it is planning to add some extra coaches to some trains on the Sundays affected.
“As well as regularly updating the media, signs have been advising drivers for some time and we continue to work with our colleagues in Traffic Scotland to best ensure everyone is able to make an informed journey decision on closure days.
“The team intends to demolish the old B800 bridge over three weekends, avoiding Remembrance Sunday.
“We will continue to work closely with our contractor to ensure every effort is made to reduce the duration of the closure and to lift the restrictions as early as is possible.”
During the closure, the bridge will remain open for local access only.
A single lane contraflow will be in place on the bridge for the duration of the A90 closure.
Diversion routes to cross the Forth for A90 traffic travelling south and north will be via the M9 (A904/5 for non-motorway traffic), Kincardine Bridge and the A985.
Diversion routes for traffic travelling north from Edinburgh will be via the M8 and M9 to Kincardine Bridge.
Local access between South Queensferry, Kirkliston and Dalmeny will remain available.
Public transport options are limited given buses will be impacted by road disruption, however trains will still be running.
A ScotRail spokeswoman said: “We will be adding extra coaches where possible, focusing on the busiest trains on each of the affected Sundays.”
Road users are encouraged to avoid the bridge area, plan their journey and make use of the live traffic updates available from Traffic Scotland and utilise public transport if appropriate.