The 0-6-0 was generally considered a switcher type, since it's lack of guiding axles meant that it was less stable at speed, yet it's lack of unpowered axles meant that all weight was adhesive weight and thus tractive effort and factor of adhesion were maximized. The 0-6-0 became possibly the most common wheel arrangement for switchers worldwide; the 0-4-0 proved to be too small and not powerful enough for most applications, while the 0-6-0 proved to be 'just right'.