Template:Blender 3D: HotKeys/3D View/Multiple Modes/GKEY XKEY XKEY
GKEY XKEY XKEY - Grabs the selection and locks its Z and Y position on the local axis. In this mode the selection will only move along the local X axis.
GKEY XKEY XKEY - Grabs the selection and locks its Z and Y position on the local axis. In this mode the selection will only move along the local X axis.