Rack-and-adhesion or pure-rack thumb|right|Traction transition section As well as the rack system used, lines using rack systems fall into one of two categories depending on whether the rack rail is continuous or not. Lines where the rack rail is continuous, and the cog-drive is used throughout, are described as pure-rack lines. Other lines, which use the cog drive only on the steepest sections and elsewhere operate as a regular railway, are described as rack-and-adhesion lines.
Rack-and-adhesion or pure-rack thumb|right|Traction transition section As well as the rack system used lines using rack systems fall into one of two categories depending on whether the rack rail is continuous or not Lines where the rack rail is continuous and the cog-drive is used throughout are described as pure-rack lines Other lines which use the cog drive only on the steepest sections and elsewhere operate as a regular railway are described as rack-and-adhesion lines