Services between Edinburgh and Glasgow, Aberdeen, Dundee, Glenrothes, Tweedbank and Dunblane will benefit from having the extra capacity.
A Tweet posted today by the rail operator said: "We'll have extra carriages on our busiest routes & more staff on hand to help."
The Tweet added that alcohol bans will also be in place.
In a statement, Scotrail also warned that trains to and from the capital will be "extremely busy," adding: "If you're heading to the game, please allow additional time for travel, as queuing systems will be in place at Glasgow Queen Street before the match and at Haymarket after the final whistle."
Scotland will play Fiji in the first home match of the Autumn Tests at Edinburgh's BT Murrayfield Stadium on Saturday, with kick off at 2:30pm.
Next Saturday's game against South Africa will kick off at 5:20pm.
The game against Argentina on November 24th will kick off at 2:30pm.