The people doing the "slamming" are either doing so to meet their own political needs or they are in search of an audience. A research team from the National Transportation Safety Board is on site within just a few hours after all transportation disasters. These are the folks who know what to do: the presence of either the President or the Secretary of Transportation is unnecessary.
Trump and the Republican Congress couldn't roll back safety regulations fast enough to please commercial freight owners. At the same time, they made traveling on AMTRAK less pleasant by cheapening products and eliminating some amenities. If there is any bipartisan fervor for conditions to improve, it is because Republicans hope that we'll forget who's to blame.