The invention relates to apparatus for singulating flat articles which are transported on-edge as a stack on a controllably driven conveyor with a stack support to the take-away station where the frontmost article is taken away horizontally in a plane perpendicular to the feeding direction. In two arbitrary ones of the pixels, which are adjacent to each other in the row direction, subpixels that represent the same color belong to the same row. The rail support device is symmetrical with respect to an intersection angle bisecting plane which is a plane developing in a vertical direction and including an intersection angle bisector. It is comprised essentially of two main parts: a case that has several features and a wheel support structure to support wheels and to secure the wheels to the case. Additional componentsfluids are included for service based on operational variables selected to determine service intervals for these components. This is achieved by swiftly reacting a disabler or neutralizer with the hazardous substance, voluntarily or by automation, on the occurrence of predetermined events that position the hazardous substance to threaten a greater than desired risk of harm.