Thank you for this interesting information.

I also wondered why trains were supposedly fatal to the law of deodands whereas ships were not. My spur-of-the-moment, totally uninformed guess was that, in the case of shipwrecks, the sea (or, more generally, the marine environment) was regarded as the killer. The scenarios that Richard Posner is writing about seem somewhat different, however, at least in that after a shipwreck more serious than a calm-water grounding, there's often nothing much to seize.