public void setBound( Track boundTrack, Node boundNode ) {
super.setBound( boundTrack, boundNode );
boundTrack.addPreSignal( this );
TrackWalker walker = new TrackWalker();
walker.startAt( boundTrack, boundNode );
walker.walkTo( mainSignal.getBoundTrack() );
distanceToMainSignal = walker.getDistanceWalked();
}