Mark Ridley-Thomas, a Los Angeles County supervisor who represents South Los Angeles, put forward a plan last year to allocate money for a Leimert Park stop and to keep the line underground along Crenshaw Boulevard. The city’s black political establishment — religious and business leaders and elected officials who have often clashed on other issues — lined up behind the effort.

“It was a salute to Tom Bradley, who said this was his vision for his city,” Mr. Ridley-Thomas said. He added that the Crenshaw line and a Leimert Park stop had become “emblematic of a struggle for progress.”

Mayor Antonio Villaraigosa, the city’s first Latino mayor, has also positioned himself as a successor to Mr. Bradley’s transit legacy: the rail lines that will span Los Angeles County in the coming decades will be a major piece of his own legacy after he leaves office next year because of term limits.

Yet Mr. Villaraigosa and his allies blocked Mr. Ridley-Thomas’s plan. Instead, a Leimert Park stop will be included only if contractors can squeeze it within the existing budget, and the Crenshaw line will run at street level for part of its trip through the area.

Mr. Villaraigosa agrees, as does just about everyone else, that Leimert Park, home to cultural festivals, jazz clubs and a host of black-owned businesses, deserves its own stop. Contractors will submit their proposals for the project within a few weeks, and the mayor said he was “fairly confident” that a Leimert Park stop could be done within the $1.8 billion budget.

But Mr. Villaraigosa also emphasized the benefits that the rail network — including a recently constructed light-rail line that carries passengers through the northern parts of South Los Angeles — would offer the area even if a Leimert Park stop was not built. He also noted his efforts to expand the Crenshaw line, which was originally designed as a bus line with a fraction of the money it now has.