Queensland Rail has slashed more than half-a-million dollars from its train drivers' annual overtime bill.

Since the 2017-2018 financial year, the driver overtime bill has decreased by 4.3% from the previous year, with worked overtime hours also decreasing by 8.2%.

The Strachan inquiry revealed these decreases are due to Queensland Rail train drivers performing unsustainable hours of overtime, which contributed to widespread train cancellations.