Sometimes you do have to sweat the small stuff -- especially when the small stuff itself is, well, sweating. And crumbling. And preventing the fullest success possible for big, expensive projects that our city leaders have struggled for years to complete.

Compared to recent massive investments both public and private, the disintegrating railroad and highway underpasses that are supposed to connect the North Shore and the North Side are truly small potatoes. But they loom large and forbidding in the pedestrian's imagination: There's not much light in there, you worry about what or who is lurking nearby, and you can be sure that something's going to drip on your head.

Entering the underpasses is a lot like spelunking. But for a little money, it could be vastly different.

In recent years, we taxpayers have invested about $350 million into the two stadiums, waterfront park and parking garage on the North Shore -- the narrow strip of land bounded on the south by the Allegheny River and on the north by a ganglion of intersecting highways. Authorities expect nearby private development to hit $429 million before it's all done -- and that's just the North Shore.

Many millions also have been raised to build, save or expand other landmarks just north of the highways, including the Children's Museum, National Aviary, Buhl Planetarium and Hazlett Theater.

So we're approaching a billion dollars recently sunk into an array of cultural institutions and private enterprises, and for just a few million dollars more, all these amenities could be united into one user-friendly package. Instead, they remain separated by a few small spaces that form a formidable barrier -- those passages under the elevated Norfolk & Southern railroad and the North Shore portion of Interstate 279.

"Synergy is very important," says Mary Navarro, senior program officer at the Heinz Endowments and a member of the Riverlife Task Force. "[These amenities] are not as easily reachable as they could be, but it's a complicated issue."

North Side community groups have been agitating to overcome the underpass problem for at least a decade. Of course, a decade passed between the time that then-Mayor Sophie Masloff suggested a baseball-only "Clemente Field" and the opening of PNC Park, but that controversial project cost $260 million. The highest amount ever suggested to improve the five underpasses and build an adjacent park is less than $6 million. Trying to follow this much smaller project is a case study in how much sweat equity is required for even the small stuff.

The Urban Redevelopment Authority commissioned a 1999 study that recommended $5.7 million in improvements to the underpasses at Allegheny Avenue and Anderson, Sandusky, Federal and Merchant streets, including a "Canal Park" that would connect to the Anderson underpass. Despite the community's pleas, the stadium authority paid $500,000 to improve only the Federal and Allegheny underpasses before the new stadiums opened. That left three unchanged, although all are used by the thousands of sports fans pouring down from free North Side parking on game days -- and by many of us city residents every other day of the year.

Now, finally, progress seems at hand. When most of the project got passed over, the URA expanded its search for federal funds. It has found them, says John Coyne, URA director of engineering and construction.

Through the Transportation Enhancement program, "if we do the design and environmental clearance work with local funds, the feds pick up 100 percent of the project costs," Mr. Coyne says. The URA expects to need about $1.2 million for a modest version of what its 1999 study recommended. This includes installing new lighting, landscaping, sidewalks and curbs; rehabbing concrete facades and steel girders; and creating a network of gutters to reduce random water drainage.

PennDOT, which channels the federal funds to the URA, is now evaluating the proposed design. Work could begin by spring.

The original study called for each underpass to complement the attraction it leads to -- a sports theme for Federal Street, an art theme for the Sandusky passage to the Warhol Museum, etc. There's no room in today's government budgets for such things, but earlier this year, the Heinz Endowments came to the rescue with a $10,000 grant to commission public art for Sandusky.

So bit by bit, a decade after the process started, the underpasses that should invite people to try all that Pittsburgh's North Side offers, may finally do so. There's light at the end of these tunnels -- and soon there'll be light inside them.