The Government body has invested £863,000 to double the number of stations where travellers can go online from the 26 already getting wifi capability.
Previous investment has seen internet access rolled out at some of Scotland's busiest stations. The second round of work, taking in Oban, Aviemore and Troon among others, is due for completion before the next ScotRail franchise begins in April next year.
ScotRail's Class 158 and Class 380 trains will also be fitted with wifi equipment after Class 170 trains were upgraded last year. By next spring, almost half its trains will be connected.
Transport Minister Keith Brown said: "We are already well on the way to ensuring online access on all of our busiest commuter routes."
Steve Montgomery, ScotRail managing director, said: "We're updating the wifi log-in process so people can stay connected when moving between trains and platforms."