This is something that has bothered me for a long time, and this question question reminded of it and motivated me to ask it here.
At the end of Back to the Future III, we see that the ravine formerly known as "Clayton", (after Clara Clayton who originally plunged to her death before Doc Brown went back to 1885 and rescued her, inadvertantly changing history) was now called "Eastwood Ravine". Why was it renamed this?
The implication is that it is because Marty, aka "Clint Eastwood" instead went over the ravine when the stolen train plunged over the edge. Since nobody knew about the Delorian (it was further down the track where nobody in the hijacked train would have seen it) and nobody knew that time travel was involved, it seems at first glance that they just put two and two together and assumed that the man they knew as Clint Eastwood had died.
But there are two problems with this theory. The first is that there were two hijackers, and the other one was known as Doc Brown. Why not call it the Brown Ravine? Doc Brown was a better known member of the community, was an established blacksmith, had his own shop, and even quite a few strange contraptions. "Eastwood" on the other hand had little in the way of ties with the town, and aside from a bit of publicity over his run-in with Buford Tannen (which he escaped alive by his wits, not any superior gun-fighting ability) was a virtual unknown. After he left the people of the town undoubtedly had to deal with his abandoned blacksmith shop, and should have put two and two together and decided Doc Brown was the train hijacker, even in the face of the second problem, which is...
Both Doc Brown and Marty wore masks when hijacking the train. Presumably, this was so their identities would not be known, and not just so they would be seen as serious about taking the train. Doc Brown, not knowing that Clara was coming after him, probably would instinctively not want her to associate him with such a deed after he was gone. In any case, the conductor and engineer on the train would likely not have seen either Doc or Marty before, as their livelihood is aboard the train and they probably did not live in Hill Valley. If they had been through the town enough to be familiar with either of the masked men it would have been Doc Brown, who had been there long enough to become established. Likewise, the other people on the train did not interact with either man so would not have been able to hear their voices or otherwise identify them.
The only person who would probably miss Marty was Séamus McFly, and it seems unlikely that he would put put two and two together and decide Marty stole the train (after his interactions with him, I find it unlikely that he would believe it something that "Clint Eastwood" would do). Even if he did I find it further unlikely that he would go sharing his suspicions with anybody.
So why, when Marty returned to 1985, was the ravine now named "Eastwood" after him?