en.wikipedia.org/wiki/Causeway

The sentence groups three examples together and says all of them carry both road and rail traffic. That is not correct for the existing King Fahd Causeway between Bahrain and Saudi Arabia.

The Bahrain national portal describes King Fahd Causeway as a 25 km sea bridge and discusses services for vehicles traveling عبر جسر الملك فهد (via King Fahd Causeway), with no rail service described. Separately, Bahrain’s Ministry of Transportation and Telecommunications says Bahrain’s future GCC rail link will run through the King Hamad Causeway project, which will be parallel to King Fahd Causeway and will include two rail tracks. In other words, the rail connection is planned on a different project, not on the present King Fahd Causeway.

So the article’s blanket claim that these example causeways “all ... carry roadways and railways” is false because one of the listed examples, King Fahd Causeway, does not currently carry railway traffic.

This sentence gives the wrong definition of overpass.

Authoritative transportation references define an overpass functionally: it is a structure that lets one road pass above another road or a railway. Length is not the defining feature. A structure does not become an overpass merely because it is a "short stretch of viaduct."

PIARC’s Road Dictionary defines an overpass as a structure, including its approaches, that allows one road to pass above another road (or a railway). The U.S. Federal Highway Administration similarly defines an overpass as a grade separation where the highway passes over an intersecting highway or railroad. Those definitions contradict the article’s statement that an overpass is simply a short viaduct.

The article is correct that the north arm of Great Salt Lake is much saltier than the south arm, but it is incorrect to say the southern part is insufficiently salty for brine shrimp.

USGS states that because Gilbert Bay (the south arm) has lower salinity than the north arm, it "supports an ecosystem rich with brine shrimp and brine flies". The Utah Geological Survey likewise explains that the south arm has a different biological community and that organisms there are a staple food for brine shrimp. Those official descriptions directly contradict the claim that the southern part is generally too fresh for brine shrimp survival.

In short: the railroad causeway did create a strong salinity split, and the north arm became too salty for brine shrimp, but the south arm is the main brine shrimp habitat, not an area broadly "insufficiently salty" for them.