When a city has been waiting for a badly needed new subway line since 1929, public art is probably far down the list of expectations, well behind accommodations like a) working trains, b) lights and c) some means of entrance and egress.

But when commuters descend into the new Second Avenue subway’s four stations, at 96th, 86th, 72nd and 63rd Streets, now set for a New Year’s Day opening — or perhaps a little later if things don’t go as planned — they will find one of the most ambitious contemporary art projects that the Metropolitan Transportation Authority has ever undertaken. The agency’s art department, M.T.A. Arts & Design, founded and first funded in 1985, is rarely — in a salmagundi system 112 years old — presented with a brand-new, blank canvas.

But lately, with the opening of the superstation at Fulton Street downtown and the extension of the No. 7 line to a new terminus on West 34th Street, the subway’s art thinkers have been able to participate almost from the beginning in incorporating installations in tile work by leading artists into stations’ designs. If the effort doesn’t always result in stations that look like artworks themselves, as some of the best stations in Europe and Asia do, it has nonetheless put the aesthetic front and center again in a way that evokes the ambition of the city’s first subway stations in 1904, with their mosaics, faience and amethyst-glass skylights.