Although class 523s are the normal power for Olten - Luzern RE services, it was a surprise to find one on an Olten - Sursee local, usually the preserve of class 560 EMUs. 523.039 scurried east from Nebikon with train 22823, the 09:37 Olten - Sursee stopper, as the fog lifted on 5 October 2012.