$ML, $MAXLINE

The maximum number of lines/tracks/trains which can appear on the screen or in a Section at one time.  This is the explicit method of limiting the number of lines.  (The implicit method is by using the ABOVE, MINSPACE and BELOW parameters).  If both are used, the number of lines is limited to the smaller of the two values.

This parameter belongs to the group of   <DimensionParameters> - it can be used only in a $SECTION command, not in a $GROUP, $LINE or $SCENE command.