Keep only sky bridge screenshot as hero image

Author: HadesScience

README.md

@@ -13,9 +13,7 @@
 </p>
 
 <p align="center">
-  <img src="images/screenshot_1.jpg" width="45%" alt="Create Train - Mountain Railway" />
-  &nbsp;&nbsp;
-  <img src="images/screenshot_2.png" width="45%" alt="Create Train - Sky Bridge" />
+  <img src="images/screenshot_2.png" width="80%" alt="Create Train" />
 </p>
 
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