Train services face eight days of disruption as the Forth Rail Bridge closes for the longest period in its 115-year history.
The landmark crossing across the Forth was opened in 1890
Network Rail said it was closing the link, which has rarely been out of action since it was built, from Sunday for "essential" maintenance.
It insisted this weekend was one of the quietest times of the year.
The closure, for repairs and paint work, will lead to the reorganisation of services.
Mary Dickson, the managing director of train operator First ScotRail, said months of work had gone into the "extremely complex operation".
"The closure will affect nearly 60% of our daily services," she said.
"Additional staff will be on hand at stations to assist customers."
Spokesman Steve Montgomery said: "Fife commuters will find quite a dramatic change to their services. There will be a mixture of trains and buses.
"Obviously, they have to look at the new timetable we've produced because it is quite a change from what you'd expect to see.
"We're also putting a lot of additional staff out next week to make sure we can guide people because it is a big change to their travelling pattern."
He added: "It's never a good week to close the Forth Rail Bridge, but there are more people on holiday at this time, fewer commuters and less disruption.
"But we do accept there will be disruption to some people and we can only apologise for that."
The company has arranged alternative routes for services between Edinburgh and Aberdeen or Inverness, as well as the new Fife timetable.
The overhaul will also involve strengthening steel work and repairs on Jamestown Viaduct in a separate £5m investment.
The £13m facelift, being carried out by at least 170 workers, involves blasting off old paint and carrying out repairs before giving the crossing a new coating designed to last 30 years.
Rail authorities said the closure was necessary to allow staff to work safely on steel close to the track.
Network Rail spokesman Keith Miller said: "What we're doing over the next eight days are those structural elements which are directly above the track that we cannot undertake without scaffolding.
"We really need that level of access to get the materials in, to get the men up there and to get the coating on.
"The length of time is the shortest duration that we can possibly do the work in."