  The electromagnetic effects on charged pion ($\pi^+,\pi^-$) spectra provide
new, independent information on the space-time evolution of the
ultrarelativistic heavy ion collision. The spectator life time and its
excitation energy may also be of importance for the understanding of the
space-time evolution of the participant zone. This paper gives an overview of
our coordinated effort to understand the interplay between electromagnetic
phenomena and processes related to the fragmentation of the spectator system at
forward rapidity in peripheral $Pb$+$Pb$ collisions at top CERN SPS energies.
Our study includes on one hand the experimental analysis of electromagnetic
effects and corresponding phenomenological Monte Carlo simulations, and on the
other hand dedicated theoretical calculations based on the Abrasion-Ablation
model ABRABLA and the 4D Langevin approach.
