There were varying degrees of guilt when killing someone in Roman law already. Suggesting that involuntary manslaughter was &#x27;invented&#x27; because of trains is preposterous. You might be thinking of corporate manslaughter but that&#x27;s an entirely different matter. You also seem to suggest that people were killed in droves because of trains not using a horn, and that the only was that was stopped was by introducing some new form of manslaughter. I hope you see for yourself how that falls under the category of &#x27;extraordinary claims&#x27;, which as we know requires extraordinary evidence.