anchor.diff:            if (trainStatusChanged(trainId, payload.status)) {
               changeStatus(trainId, payload.status);
             }
  -          if (trainLocationChanged(trainId, payload.location)) {
  -            // Update graphic attributes with new location
  -            // The status attribute is updated by the preceeding function
  -            // The other attributes such as speed will have to be updated too
  -            graphic.attributes.latitude = payload.location.latitude
  -            graphic.attributes.longitude = payload.location.longitude
  -            point.setLatitude(payload.location.latitude);
  -            point.setLongitude(payload.location.longitude);
  -            graphic.setGeometry(point); // This is necessary to move the Graphic
  +          // The following test is to protect against a raw model train message that is published to the augmented topic
  +          if (payload.hasOwnProperty('location')) {
  +            if (trainLocationChanged(trainId, payload.location)) {
  +              // Update graphic attributes with new location
  +              // The status attribute is updated by the preceeding function
  +              // The other attributes such as speed will have to be updated too
  +              graphic.attributes.latitude = payload.location.latitude
  +              graphic.attributes.longitude = payload.location.longitude
  +              point.setLatitude(payload.location.latitude);
  +              point.setLongitude(payload.location.longitude);
  +              graphic.setGeometry(point); // This is necessary to move the Graphic
  +            }
  +          } else {
  +            console.log("Have not got a location");
             }
             // Update Popup after updating sensor values and speed
             graphic.attributes.temperature = payload.temperature;
  
positive.code:       function createGraphic(trainId, payload) {
          var graphic = null;
          var pms = null;
          var point = new esri.geometry.Point(payload.location.longitude,
                                              payload.location.latitude,
                                              new esri.SpatialReference({
  
negative.code:       }
  
        function onMessageArrived(message) {
          console.log("In onMessageArrived, payload is " + message.payloadString);
          var topicParts = message.destinationName.split("/");
          var trainId = topicParts[2];
          var payload = JSON.parse(message.payloadString);
  