document: Members of the RMT union will walk out for 48 hours from Sunday 7 August, 24 hours on Thursday August 11 and over the weekend of 13/14 August.
  The RMT is against the increased use of trains on which the driver opens and closes the doors at stations.
  ScotRail has said such operations are already common on the network.
  RMT general secretary Mick Cash said: "Recent rock-solid strikes on ScotRail have been supported by the travelling public who understand that the staff are fighting for the basic principles of rail safety.
  "In spite of this, Abellio/Scotrail continue to ignore the strength of feeling amongst their staff and passengers over the extension of driver-only operation."
  ScotRail says 59% of customers already travel on a train where the doors are safely opened and closed by the driver, and insists that the job, pay and conditions of conductors are guaranteed.
  Phil Verster, managing director of Scotrail Alliance, has previously said: "This industrial action by the RMT is not about safety, it's not about a second person on a train and it's not about jobs or pay and conditions.
  "It is about modernisation of the railway and preparing us for a railway that Scotland can be proud of for the next 40 or 50 years."
summary: Workers on ScotRail are to stage a fresh wave of strikes in a long-running dispute over the increased use of trains without guards.