The extra trains are due to run between Edinburgh and Prestonpans from early afternoon onwards. All trains will serve Wallyford and Musselburgh stations, near to the finishing line.
ScotRail also advise that, due to platform extension works, a small number of services will start or terminate at Haymarket, rather than Edinburgh Waverley.
A ScotRail Alliance spokesperson said: “Please allow extra time for travel, and buy your ticket in advance, not on the day. The last trains of the day are likely to be busy, so please aim for an earlier service to avoid disappointment.”