Almost 100 services have been cut from Sydney's train network starting today.
Management confirmed on Thursday it will be making some "tweaks" to the timetable introduced in November 2017, but is promising minimal impact.
Most of the 94 services to be axed are off-peak trains running between 7pm and 6am on weekdays, and a small number on weekends.
They make up less than one per cent of the thousands of services run each week, affecting mostly the Northern, North Shore, Bankstown, Inner West, Cumberland and Carlingford lines.
"This timetable has proven itself during normal operation and routine incidents, but we recognise that we need to be smarter about how we use our crew so we're better placed to keep customers moving during bigger disruptions," Sydney Trains chief executive Howard Collins said in a statement.
The changes will free up more drivers and give greater capacity to deal with delays when incidents occur, a spokesperson said.