If your loco hesitates when it first begins to roll, you may need to adjust the motor tunings in the “settings” screen for your loco. Enter the settings screen (which is accessed from the “cog” button at the bottom of the train control screen). Scroll to the bottom of the settings screen where you will find the motor tunings (Start Voltage, Update Period, Differential). Try adjusting these settings to an alternate value till your loco starts smoothly.