The claim is completely irrelevant to what happened in Ohio. For starters, the train did not have braking issues. Rather, it derailed because of a broken axle. Further, the train was not carrying oil, which is what the Trump-era regulation rollback specifically pertained to.

Also, and while it’s been a bit of an open question at times, hasn’t Joe Biden been president for the last two years? If that regulation was so effective and great, why didn’t Buttigieg try to reinstate it, even if it led to a court battle? He’s bringing up a completely unrelated regulation as a way to put Trump in the middle of the situation when he’s been in charge for the last two years. How does that square?