For straphangers who have spent their lives standing on dank subway platforms -- quietly taking inventory of each station's shortcomings -- please know you're not alone.

State Comptroller Thomas DiNapoli has issued his own survey, and ordinary riders don't know the half of it.

Only 51 of the city's 468 subway stations are in good repair, DiNapoli concludes. And the rest?

Every New Yorker knows that litany of woe.

It includes stations sporting walls stained brown with a mystery drip that looks like rust. It includes stations where tile work is falling in unsightly chunks. It includes stations where paint is peeling on pipes and beams.

And then come harder-to-spot structural deficiencies. DiNapoli says a third of station platform components -- like ceilings, floors and columns -- have problems.

To give the MTA its props, it has spent $4.5 billion to renovate 241 stations over the last three decades. But the comptroller says the agency has historically scrimped on maintenance. So stations in the century-old system have quickly returned to their familiar seediness.

That's a fast track to nowhere -- a mistake the agency cannot afford to repeat.

The MTA points out that it has shifted its strategy to avoid full-station overhauls. With a limited budget, it targets first the most deteriorated structural components within stations.

That might make sense temporarily. The MTA is in a full-tilt scramble to find new funding streams for the five-year, $32.5-billion capital plan.

Fare-paying passengers are tapped out, and so is every other current revenue source.

Giving priority to structural issues is simple triage.

But it won't do to let millions of subway riders stew indefinitely in gloomy, grungy stations. New York is a better city than that.

On the surface we're booming -- from Park Slope and Williamsburg to Long Island City and the West Side. So why the ambience of a medieval dungeon in our stations?

Find the money and make them better.