Out of control trains!

src/Station.ts

@@ -1,4 +1,28 @@
+import { distance } from './utils';
+
 export default class Station {
+  // Utility methods for working with arrays of Stations
+  public static largestStation(stations: Station[]): Station {
+    let largest: Station = null;
+    for (const station of stations) {
+      if (largest === null || station.population > largest.population) {
+        largest = station;
+      }
+    }
+    return largest;
+  }
+
+  public static stationsWithinRadius(stations: Station[], point: PIXI.Point,
+                                     radius: number): Station[] {
+    return stations.filter(station => distance(point, station.location) <= radius);
+  }
+
+  public static closestStation(stations: Station[], point: PIXI.Point, num: number): Station {
+    return stations.reduce(
+      (prev, curr) => distance(point, prev.location) > distance(point, curr.location) ? prev : curr,
+    );
+  }
+
   public location: PIXI.Point;
   public population: number;
   public connections: Station[];