Hi there, I've noticed a small part that is uncharted on this map and since I don't really know how to do it myself, I'll say what I've found missing so that hopefully someone can add it and make the map complete.
From platform 1 next to south railroad outpost there is a way west. This area is to be designated as platform (?). This platform then has a connection north and leads to platform 5 (the entrace to kidnaped train, the way isn't open for me but I guess it's because I haven't got the quest or I need to blow the door open with explosves). From there it connects north to platform 4. Now there are 2 more uncharted passages. Through the platform there is a passage north with leads to platform (?) which is a dark area. In here there is a ladder that gives passage to a room within the same map. The place is infested with crawlers. There is a hole in the wall which leads into a cave and inside the cave there is a hole in the ground with a passage down, this is just a small arena with a black crawler. After exploring this the platform has an exit north again leading to platform (?). It is also a dark area and it has 3 crawlers inside a small room as well as some lurkers. This area also has another passage north which connects to Platform 2 which is close to rail crossing.
So it's just those 4 areas. The 3 platforms that connect south railroad outpost to rail crossing and the black crawler arena.
These zones were added with Version 1.0.1.4 to make it easier for players to find the Missing Train during its respective quest by simply following the tracks from SRO (where the train departed from) until you hit Rail Crossing, as opposed to having to do it the other way around like you did in the EA releases.
I know there was a guy on Steam who was creating his own map of Underrail with this new segment included, but I haven't heard from him nor seen an update of the map since he started making it half a year ago, so I guess he must have just abandoned the project.
Off the top of my head, I can't think of any other areas that were added in 1.0.1.4 or in the newest experimental build (up to Core City, at least), but I did notice that it is now possible to access lu-a6 from lup-a2 without having to use TNT, if it wasn't before.
