There's no bead, or overflow. So unless they paid someone hours to grind that down to square form…. I 2nd this. No weld was ever performed in that vicinity.
Would it be possible for a temporary jumper to carry the current?
That's the trick, tho. Nothing left behind. A sheet of aluminum foil? 1st car runs over it, destroys it, circuit breaks, signal lights, but too late?
Low current with a high interference allowance.. That brace laying under the damage could have jumpered a signal through. Vibrations would have dislodged it, but again… Too late.