Members of the RMT union will head for Holyrood on Wednesday, the same day as a debate on the issue, which has already led to two periods of industrial action.
Union bosses claim that ScotRail is putting passenger safety at risk by planning to run services without guards on the new route, which is due to open at the end of the year.
But ScotRail says passengers' safety will not be compromised, adding that services elsewhere on the network have operated without guards for 30 years.
Bob Crow, general secretary of the RMT, said: "The role of the Scottish Government in colluding with ScotRail to axe the guards on their trains is now very clear and we also have confirmation that the attack on staff on the Airdrie-Bathgate route is the thin end of a wedge.
"On the eve of the election we are giving the opportunity to the SNP to distance themselves from this dangerous stitch-up, reaffirm the commitment to the safety-critical role of the guard and confirm that there will be no taxpayer bail-out of ScotRail's strike-breaking operation."