  We study the exact Time-Dependent Potential Energy Surface (TDPES) in the
presence of strong non-adiabatic coupling between the electronic and nuclear
motion. The concept of the TDPES emerges from the exact factorization of the
full electron-nuclear wave-function [A. Abedi, N. T. Maitra, and E. K. U.
Gross, Phys. Rev. Lett. \textbf{105}, 123002 (2010)]. Employing a 1D
model-system, we show that the TDPES exhibits a dynamical step that bridges
between piecewise adiabatic shapes. We analytically investigate the position of
the steps and the nature of the switching between the adiabatic pieces of the
TDPES.
