The large gray object in the hole in the cab I believe is a collision post designed to help protect the crew from crushing in the event of an accident. It appears the cab is fairly intact so my guess would be one of two. Either it was the lead engine that rear ended a freight hitting something like containers which crushed the sheet metal or was the trailing unit where the cars behind the engine was forced into it during a cars. hitting another engine wouldhave done a different type of damage in my opinion.