I wanted to see if anyone can find the video where the animated train sequence is from?
I dont think we ever got an answer about what the train meant, but it's a small animated scene, walking through a train carriage. I believe it was in his minecraft series
@dying-ship-and-sea-of-dead-stars
Had to go back and check, but it is in the Minecraft series, specifically Part 16: LAVA IS HOT HAHAHaha..., starting at about 15 seconds in (right after the Iron Golem gives Mark a "'sup") and going until about 0:39.
It's more auditory, the sound of a train picking up speed and a train whistle along with a distorted/sped-up song of some kind. For a brief moment there is an (extremely dark) image of a door that gets farther away, presumably at the end of a train corridor considering the sounds.
My attempt at upping the brightness/contrast of the door:
(There's a reason I don't usually bother trying to do this sort of thing: I'm not very good at it! But the door in the second image does seem to be distorted/glitching, going by the broken lines of the door's paneling at the top and bottom.)
Here's a not edited screenshot for comparison:
Listening to the audio, the music playing does sound like a jazzy version of "Skip to My Lou," which while doing a Google search to see if I could find the original version Mark might have used and doing a quick scan of the Wikipedia page on the song, uh...
"Skip to My (The) Lou" (Roud 3433 and 3593) is a popular American folk song and partner-stealing dance from the 1840s. Carl Sandburg, poet and biographer of President Abraham Lincoln, writes that "Skip-to-my-Lou" was a popular party game in Lincoln's youth in southern Indiana, with verses such as "Hurry up slow poke, do oh do", "I'll get her back in spite of you", "Gone again, what shall I do", and "I'll get another girl sweeter than you".[1] John A. and Alan Lomax wrote that "Skip to My Lou" was a simple game of stealing partners (or swapping partners as in square dancing). It begins with any number of couples skipping hand in hand around in a ring. A lone boy in the center of the moving circle of couples sings, "Lost my partner, what'll I do?" as the girls whirl past him. The young man in the center hesitates while he decides which girl to choose, singing, "I'll get another one just like you." When he grasps the hand of his chosen one, the latter's partner moves to the center of the ring. It is an ice-breaker, providing an opportunity for the participants to get acquainted with one another and to get into a good mood.[2] "Skip to My Lou" is number 3433 and 3593 in the Roud Folk Song Index.
Lyrics that include "I'll get her back in spite of you" and "a simple game of stealing partners" you say?
Well, it would certainly be thematic if Mark had been considering making a train-themed follow-up to WKM, that's for sure.