Reckless driving is usually if you exceed the target speed by too much, for example when braking too late for a station. If you also brake too heavily, you might exceed the max comfortable acceleration (or, rather, deceleration) which I took to be 1m/s^2 according to some source. Exceeding passenger comfort means too abrupt change in the acceleration, most likely when coming to a halt after maximum braking. You can avoid this by releasing the brakes just before the train is about to stop. Bear in mind that the performance of the tread brakes on these trains varies according to speed. The brakes are more effective when the train is moving slowly.
The violations are recorded every two seconds if I recall correctly, which explains the number of occurrences!