aighes
(Henning)
3
Hallo,
danke für den Hinweis. Ich hatte das Projekt Marker sichtbar bekommen schon aufgegeben. 
Hier noch der vollständige Code für Karte, Track und Marker.
var mapquest_osm = new L.TileLayer("http://{s}.mqcdn.com/tiles/1.0.0/osm/{z}/{x}/{y}.png", {maxZoom: 18, minZoom: 1, attribution: "© 2012 MapQuest - Map data © <a href=\"http://www.openstreetmap.org/\" target=\"_blank\">OpenStreetMap</a> and contributors, <a href=\"http://opendatacommons.org/licenses/odbl/\" target=\"_blank\">ODbL</a>", subdomains: ["otile1","otile2","otile3","otile4"]});
var mapnik_osm = new L.TileLayer("http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png", {maxZoom: 18, minZoom: 1, attribution: "Map: © 2012 <a href=\"http://www.openstreetmap.org/copyright\" target=\"_blank\" style=\"\">OpenStreetMap</a> contributors"});
var hikebike = new L.TileLayer("http://toolserver.org/tiles/hikebike//{z}/{x}/{y}.png", {maxZoom: 18, minZoom: 1, attribution: "<a href=\"http://hikebikemap.de\" target=\"_blank\" style=\"\">HikeBikeMap.de</a> Map data © <a href=\"http://www.openstreetmap.org/copyright\" target=\"_blank\" style=\"\">OpenStreetMap</a> contributors"});
var track = new L.GPX("track.gpx", {async: true}).on("loaded", function(e) { map.fitBounds(e.target.getBounds()); });
var LeafIcon = L.Icon.extend({options: {iconSize: [16, 28], iconAnchor: [0, 28]}});
var startIcon = new LeafIcon({iconUrl: "pin_start.png"}), zielIcon = new LeafIcon({iconUrl: "pin_ziel.png"});
var markerLayer = L.layerGroup();
var marker1 = L.marker([lat1, lon1], {icon: startIcon}).addTo(markerLayer);
var marker2 = L.marker([lat2, lon2], {icon: zielIcon}).addTo(markerLayer);
var map = new L.Map('map', {center: new L.LatLng(50, 10), zoom: 5, layers:[hikebike, track, markerLayer]});
map.addControl(new L.Control.Scale());
map.addControl(new L.Control.Layers({"HikeBikeMap":hikebike, "MapQuest Open":mapquest_osm, "Mapnik":mapnik_osm}, {"GPX-Track":track, "Marker":markerLayer}));