Corrected entry: The main plot device is the lack of petrol. The Doc has an ice generating machine and lamp oil. The ice-generating machine is steam driven and works at ambient temperature. Therefore it is fair to assume that it uses pressure transformation to achieve freezing. It should be fairly simple to rebuild the compression equipment from the icebox into a small scale cracking unit. The required technology is similar. Cracking is the process of breaking down heavy oils like lamp to light ones like petrol. At this point in the film they have several days which should be plenty of time to do this. This would be a much safer course of action.
Corrected entry: If the 1955 Doc saw his tomb and sent Marty to 1885 he shouldn't be surprised to see him in 1885, since the Doc that's in 1885 is the same one who sent him there in 55, and hence has already seen his tomb. Some people argue it's not the same Doc, but time travelling doesn't magically create a new human being! The 1955 Doc sends Marty back to 1885, ages 30 years, invents a time machine, travels around, and ends up in 1885. 30 years may dull the memory a bit, but I think you'd remember sending someone into the past to rescue yourself...
Correction: Actually, the Doc that is in 1885 is the Doc from 1985. The letter that Marty receives in 1955 is from the Doc who was from 1985 not 1955. Therefore, when Marty goes back to rescue Doc, he's actually rescueing the Doc from 1985. The 1955 Doc saw his tomb but when Marty goes back, the Doc really isn't suprised to see Marty. All he said was that "he gave him specific instructions not to come for him" and what was it. He also said that "it was good to see him", not "what are you doing here" I think he knew Marty would come for him.
Corrected entry: The fuel problem for the DeLorean is a non-issue. Internal combustion engines can and do run on alcohol, and there was plenty of alcohol available in the Old West.
Correction: The problem wasn't the fuel; it was the damage done to the car from their attempt to use alcohol as fuel. As you know, they tried using alcohol (some booze of some kind), and it caused an explosion that Doc said would take a month to fix. Since the photo of the headstone said Doc was going to be shot on Monday, they didn't have time to fix it. Perhaps if they would have used the right kind of alcohol, the explosion wouldn't have happened...
Corrected entry: During the final train sequence, how does that gauge in the Delorean measure the pressure inside the train, when nothing is physically attached between it and the Delorean to measure that?
Correction: It could be more like a watch, telling the time needed for the 3 things to blow up. Doc could have measured that time.
Corrected entry: As per http://www.bartleby.com/65/in/intern-co.html, J. J. É. Lenoir built the first gasoline powered internal combustion in 1859. De Rochas patented a design in 1862, and Otto built an engine in 1878. Gottlieb Daimler built what is considered the ancestor of today's internal combustion Engine in 1885. All this is by way of saying that gasoline would not have been impossible to find in 1885...especially considering that Edmund Drake drilled America's first oil well in 1859.
Correction: 1) Internal combustion engines were not running rampant, so there wouldn't be any places to get gasoline. 2) Engines evolved a ton from 1885-1985. The fuel used 100 years ago was completely different and wouldn't have worked in a Delorean.
Corrected entry: When the DeLorean suddenly appeared in 1885, the Indians have absolutely no reaction at all. There is no possible way that they wouldn't have been the least bit spooked or confused, and we should have seen some semblance of this in their actions, but they just keep charging on like nothing happened. It'd be like a an alien spaceship appearing out of nowhere in Times Square and people not even batting an eyelash.
Correction: Even putting aside that not reacting the way you expect is not a mistake, they were more focused on being chased by the cavalry, and they may well have assumed the Delorean was another "white man" invention like the locomotive.
Would it not be a bit mysterious if the Americans had invented the car but still ride horses?
The Indians did not know that it was a car or what its purpose was. All they saw was a strange device obviously invented by the "white man."
Corrected entry: In 1885 Marty meets his great-great-grandparents. His great-great-grandfather looks like him so that we can be sure of their relation. BUT, his great-great-grandmother looks like his own mother. This makes no sense as in this way his parents are related by blood due to the resemblance of their ancestors.
Correction: Even if a blood relationship is implied, it still isn't close enough to be an issue. My great-great-grandfather and my wife's great-great-great-grandfather were the same person. Perhaps it's merely an implication that the McFlys and the Baines are two families destined to be together. Or perhaps she simply happens to look like Marty's mother and has no genetic relationship to her whatsoever.
Corrected entry: In the opening scene when Doc wakes up he turns on the TV to hear "Hey kids, what time is it? It's Howdy Dowdy time." Doc, on the phone, says the time is 7 o'clock AM. Any smart baby boomer knows that Howdy Dowdy aired at 5:30 PM EST. (00:05:17)
Correction: Look at the mass of electronics on top of the television. It's likely that Doc has constructed a recording device and is using a recording of Howdy Dowdy as an alarm clock (remember his facination with the modern video camera in Part 1). We also know from the beginning of Part 1 that Doc has an obsession with setting alarm clocks.
Corrected entry: At the very end of the movie when Marty and Jennifer are at the wreck on the train tracks, the thing starts dinging and the arms lower, indicating that a train is coming. But if Doc is coming from somewhere else in time, then it wouldn't say a train was coming, and one dosn't come later.
Correction: He can travel through time, I don't think it would be so hard to make a train signal activate.
Corrected entry: Doc could not have the copy of the pic of him and Marty at the clock of the tower, because Marty has it in the DeLorean when he comes back to 1985.
Correction: The technology existed in 1885 to produce duplicate copies of the same photograph. The photographer who took it would certainly be able to do so there and then. Even if that wasn't the case it's not a stretch that someone of Doc's abilities could manage it so that he and Marty could each have their own copy.
Correction: It's certainly possible that they got more than one photograph taken.
Correction: There are several instances of duplicate (doppelganger) items and characters in the same timeline throughout the BTTF trilogy. For example, the DeLorean itself exists two and even three times within the same timeline. Doc and Marty and Jennifer and Biff all exist as doppelgangers within the same timeline. So, a duplicate photograph should be no problem in a storyline riddled with such inconsistencies.
This is incorrect... there is only 1 Marty, 1 Biff, 1 Doc, 1 Jennifer and 1 DeLorean. Yes, multiple versions may exist at the same time but in no instance is there a copy of the original person or car. For example, in BTTF II in 1955 there are 2 Marty's at the dance at the same time but the 2nd newer Marty is the same Marty from BTTF I. There should only be 1 copy of the picture, on the other hand, because it has not (to the best of our knowledge) been time traveling. The only explanations (for it to not be a mistake and these are still guesses) could be that they had a second picture taken even though it might be an expensive and time consuming process or Doc Brown could have gone into the future and taken it from Marty and, therefore, the picture could exist twice in 1 time period.
The photo time-travels at least twice in BTTF3: Once with Marty in the DeLorean on the explosive return trip, and again a few moments later when Doc arrives in the steam-powered locomotive time machine. We can reasonably assume that there was another, time-erased meeting between Marty and Doc (possibly in the future) wherein Marty explained how the photo was destroyed, prompting Doc to go back to the Old West and procure the photo again. Same exact photo X2, same scene, just as there were multiple characters and vehicles in the same timelines.
Correction: It take a considerable amount of pressure and heat to perform cracking, over 9000kpa and 2000 degrees Centigrade, and even after that the product has to be filtered to remove any remaining inpurities. Also they had no technology to test the "petrol" to see if it was the right compound to be used as fuel for a car.