The Soo Line Smash

On a fine August day, Timmy and his dog, Laddie, were walking along defendant Soo Line's railroad tracks when a Soo Line freight train approached. Laddie did not heed the warning whistle, and Timmy jumped back into the path of the oncoming train to rescue his dog. Laddie was unhurt, but Timmy sustained serious damages when struck by the train. Timmy's parents sued the Soo Line for negligence in the operation of its train.

At trial, plaintiffs offered evidence of a recent U.S. Department of Transportation Assessment report that Soo Line had a comparatively high system-wide accident rate.

What ruling and why?