The idea of visit depots packed full of locos on Sundays disappeared many years ago on British Railways. This gallery was taken at Acheres depot to the west of Paris with more than 160 locos present on a Sunday covering more than 10 different classes!
http://www.world-railways.co.uk/gallery/gallery.php?id=216
http://www.world-railways.co.uk/gallery/gallery.php?id=216