Considering the 450s don't have gearboxes.
'Gearing' on modern units is normally a software mod that affects acceleration rather than changing out physical gears. On Desiros (like most modern trains) the traction motors directly drive the wheels. The 450s have been used on Hounslow rounders and Weybridge bays since day one and it doesn't get much more stop/start as that. The issue has stemmed from the doors which close quite slowly and the are quite easy for passengers to hold open which has made keeping to time an ongoing struggle.