A total of more than 80,000 supporters are expected at Murrayfield and Tynecastle, where Hearts take on St Mirren this afternoon.
ScotRail has planned for one of Edinburgh’s biggest ever sporting days by adding extra carriages on almost 100 trains which arrive into Haymarket between 11.15am and 2.15pm, and leave between 4.30pm and 7.30pm.
The move follows complaints from fans who attended last Sunday’s Scotland v New Zealand match who claimed there were not enough trains to take them to and from the game.
The train operator stressed that “every available carriage” will be used to help supporters today.
But the firm stressed that queues at Haymarket will be “inevitable”, particularly if fans arrive over a short period of time after the games.
Scotland, led by captain Kelly Brown, kick off against South Africa at 2.30pm.
Hearts against St Mirren gets under way off at 3pm, with a 17,000 full house anticipated.
ScotRail will operate queuing systems at Haymarket to guide people towards available trains.
More than 60 extra staff will be on duty to assist travellers.
A spokesman said: “We have made every possible effort to provide thousands more seats.”