



 
Hi Normand, When you built the scale model you said "at exact half scale in all dimensions" but in your mind you only cut the steel bar in half in one dimension. You need to cut the length, width and height in half so the volume of the scale model is 1/2 × 1/2 × 1/2 = 1/8 times the volume of the locomotive. Since the weight is proportional to the volume the weight should be 1/8 × 300 = 37.5 tons. I hope this helps,  


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