[1] It runs between Hundige and Hillerød, serving all stations on the inner part of the Køge radial.

Before that time the most constant characteristic of service A was that it ran on the Klampenborg radial in the northern end of the system.

Until 2007, separate service designations were used for trains that reinforced the basic service on the Køge radial in high-traffic periods.

The first supplementary service was the rush-hour Ax which started running when the first phase of the Køge radial opened in 1972.

It was upgraded to the daytime K service in 1992 and quickly renamed to A+ in 1993.