No, the specific issue that was being discussed was SAFETY inspections, which mostly ensure that the brake lines are working and are properly attached and that the brakes are not stuck on.
Nobody wants their train brakes catching fire, so they are pretty good about making sure this inspection goes well.
One railroad has ONE train that starts in Mexico, and runs directly to a place in the United States with no stops, and therefore no connecting/disconnecting additional railroad cars. But current regulations require that this train stop at the border and get a safety inspection by american union crews. This slows down the train, costs a lot of money paid for the 2nd inspection, and clogs up the border (slowing down more trains).
This has nothing to do with inspecting cargo.
And it illustrates the advantage of working together. If we can ensure that the safety inspection checklists are the same in Mexico, America, and Canada, we don't have to inspect everything everytime it crosses the border.
Just as, if we had common car regulations, you could import a car from Europe without having to jump through hoops and spend thousands on "upgrades".
Charlie, you are behind the times. The EU regulations are the same as California's, making Eurovehicles street legal in 50 states.