Bridges and barracks in an East River postcard

This 1940s technicolor postcard shows the sturdy Triborough (aka the Robert F. Kennedy) Bridge in the foreground and the stunning Hell Gate Bridge, which carries rail traffic, behind it.

It’s only one leg of the Triborough though; the bridge connects the Bronx to Manhattan to Queens—leapfrogging over the joined-via-landfill Randall’s and Ward’s Islands.

I’m curious about the barracks-like white and red buildings in the background on what looks like Randall’s and Ward’s Islands. In the 1930s, the island became home to a psychiatric hospital that still operates today; it replaced an older insane asylum.

Are these barracks part of the psych hospital—or used as housing for some other group of people the city didn’t want in Manhattan or the the other boroughs?