"A few years after the 1900 riot [in which whites attacked blacks in midtown following the stabbing of an undercover police officer by a black man], as Harlem land values increased with the first subway line nearing completion in 1904, the black residents, once sought as renters in Harlem, became the targets of an organized removal effort by some white Harlem property owners."
"The [New York Herald] article also suggested that a rent increase “which the parlor car porters could pay, but their colored inferiors could not,” had previously been used as a strategy to remove the undesirable tenants."
Addendum: here's a direct citation for Harlem rent hikes precipitated by subway construction in 1904 making the neighborhood more accessible to low-income would-be-renters: https://www.gothamcenter.org/blog/the-end-of-the-african-ame...
"A few years after the 1900 riot [in which whites attacked blacks in midtown following the stabbing of an undercover police officer by a black man], as Harlem land values increased with the first subway line nearing completion in 1904, the black residents, once sought as renters in Harlem, became the targets of an organized removal effort by some white Harlem property owners."
"The [New York Herald] article also suggested that a rent increase “which the parlor car porters could pay, but their colored inferiors could not,” had previously been used as a strategy to remove the undesirable tenants."