In order to keep the bricky appearance of the train engine intact, [Robert] hollowed out a few cheap imitation LEGO bricks to house the electronics. He also cut out slots for JST connectors ...

And there are over 250 thousand LEGO pieces in it. Now, you may think this battle is the one from the end of Attack of the Clones. The one where Yoda whipped out his lightsaber for the first time.