I seem to recall that, after UP 6936 had a fatal encounter with a gravel hauler, in which gravel entering in through the nose door killed a crewman in the cab, UP welded the nose door shut.

That's great - for 6936. But UP's got a couple thousand other cowl cab units with nose doors. Certainly they were not all welded shut (I see them open in the yards all the time). As far as I know, none were.

So what's the rationale for welding the door on 6936, but not on any of the others? Publicity? Poorer design (maybe the Centennials were more vulnerable to this kind of accident)? Or is it just too much trouble to fix it for all the regular crews?