Track Markers

Quick noob question: when I try to add markers on the tracks, it won't let me drag them for a distance. How do you extend a marker over a span of, say 500 feet of track?
https://www.railworksamerica.com/forum/
https://www.railworksamerica.com/forum/viewtopic.php?f=7&t=11237
dfcfu342 wrote:After placing the marker you can drag the ends of the marker to the point you desire. It will automatically center the marker over your chosen length.
buzz456 wrote:" zigs in one direction and then zags" Serious technical talk.![]()