diff --git a/static/js/overlays/TrainOverlay.js b/static/js/overlays/TrainOverlay.js
index 4bd19ab..badf7a3 100644
--- a/static/js/overlays/TrainOverlay.js
+++ b/static/js/overlays/TrainOverlay.js
@@ -179,7 +179,8 @@ export default L.LayerGroup.extend({
 
   },
 
-  onAdd: function(/*map*/) {
+  onAdd: function(map) {
+    this.map = map;
     this.layerMgr.addListener(() => this.reDraw());
     this.wsChannel.addListener("minetest-info", () => this.onMinetestUpdate());
     this.reDraw();