At the Farris Halstead Library train station in the Loop, if you follow the tracks to the east, you will discover a junction where opposing straight tracks from the north and south intersect with the eastward tracks. These eastward straight tracks are unusual in that they appear to continue and stop before the edge of the elevated platform with no bumpers to mark the end of it, appearing unfinished, although it should be noted that no trains traveling eastward will actually go down these straight tracks all the way due to the curved transition tracks guiding them away. In the real-life Loop in Chicago, this spot would be located at the junction right after the Harold Washington Library train station, which unlike its depiction in Watch Dogs has no straight tracks continuing after the curved tracks at all.

This detail is notable because the day before Watch Dogs' release in May of 2014, an anonymous developer claiming to have worked on the game posted to 4chan their insight on the game's development and experience working with Ubisoft Montreal, including details on how the train tracks worked in earlier builds of the game that may be talking about this unfinished intersection:


In 2020, an early build of the game dated to September 21st, 2013 was dumped online by YouTuber JustAnyone, but it's currently unknown if this mistake existed in this build.