Hello, my name is Natalie and I will be telling you about tunnel boring machines. The tunnel boring machine is a really big machine that has drills in the front. The tunnel boring machine is used for making tunnels for the subway. It can break through giant rocks. The front of the tunnel boring machine used to be yellow, but it is not yellow anymore because it got too dirty!
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| This is a Tunnel Boring Machine underground. It is yellow because it's clean. |
