Add amtrak train live location layer

layers/amtrak-routes/layer.js

@@ -0,0 +1,26 @@
+import VectorLayer from 'ol/layer/Vector';
+import {Vector as VectorSource} from 'ol/source.js';
+import GeoJSON from 'ol/format/GeoJSON.js';
+
+import {Style, Stroke} from 'ol/style.js';
+
+import url from './data.geojson?url'; // TODO: remove `?url`?
+
+const colors = '0,83,126'; // from their website's cookie banner, and other places
+
+const vectorLayer = new VectorLayer({
+    source: new VectorSource({
+        url: url,
+        format: new GeoJSON,
+    }),
+    style: function(feature, resolution){
+        return new Style({
+            stroke: new Stroke({
+                color: `rgba(${colors},${Math.min(1, Math.pow(resolution/10, 1/4))})`,
+                width: 10/Math.pow(resolution, 1/4),
+            })
+        });
+    },
+});
+
+export default vectorLayer;