Named after its creator Ernst Maelberg
, a Maelberg Variance is said to take effect around a station when its line velocity is in a dual state. This frequently occurs when a stacked velocity change takes place just as another place affects the station, where the resulting velocities are in opposite directions. Prior to 1971, the latter state always got preference, but the introduction of Maelberging saw the emergence of the two-state condition as legal.
Players must be able to ride both velocities to enter the station - rarely is this the case, and a carefully planned Maelberg Variance can often be more effective than any standard Block.