I was thinking about that after reading one of the earlier posts of the week. If it is location based, the flicker might be installed below the rails instead, giving you the feature on whichever loco cars you like (reed sw. & magnet could basically ID which and when.)
Aren't there random timing boards on the bay? It was often as easy as an IC swap or clock jumper wire on the timer boards I used to work with to get a random number generated.... I mean; they seem to have everything else.
