don't show train tracks when zoomed out (#2131)

## Description:

When zoomed out the tracks don't alias well and makes the map too busy.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/client/graphics/GameRenderer.ts

@@ -236,7 +236,7 @@ export function createRenderer(
   const layers: Layer[] = [
     new TerrainLayer(game, transformHandler),
     new TerritoryLayer(game, eventBus, transformHandler, userSettings),
-    new RailroadLayer(game),
+    new RailroadLayer(game, transformHandler),
     structureLayer,
     new UnitLayer(game, eventBus, transformHandler),
     new FxLayer(game),

src/client/graphics/layers/RailroadLayer.ts

@@ -9,6 +9,7 @@ import {
   RailType,
 } from "../../../core/game/GameUpdates";
 import { GameView } from "../../../core/game/GameView";
+import { TransformHandler } from "../TransformHandler";
 import { Layer } from "./Layer";
 import { getBridgeRects, getRailroadRects } from "./RailroadSprites";
 
@@ -27,7 +28,10 @@ export class RailroadLayer implements Layer {
   private nextRailIndexToCheck = 0;
   private railTileList: TileRef[] = [];
 
-  constructor(private game: GameView) {
+  constructor(
+    private game: GameView,
+    private transformHandler: TransformHandler,
+  ) {
     this.theme = game.config().theme();
   }
 
@@ -91,6 +95,11 @@ export class RailroadLayer implements Layer {
 
   renderLayer(context: CanvasRenderingContext2D) {
     this.updateRailColors();
+    if (this.transformHandler.scale <= 2) {
+      // When zoomed out, don't show the railroads
+      // to prevent map clutter.
+      return;
+    }
     context.drawImage(
       this.canvas,
       -this.game.width() / 2,