Outside, it was nearly spring in Louisville, the sky lousy with rain. Inside, the aisles were flooded with gawkers and buyers. The show booths were expensive and expansive. Not a frown in sight, the air felt pumped with optimism.

Such was the scene at last month's annual running of the Mid-America Trucking Show. Unlike what's heard at many such trucking events, this time out the biggest complaint by many suppliers was that they were so busy in their booths, they never got to "walk" the show themselves.

That's not much to squawk about. But it exemplifies how easy it is to see a cloud outside the silver lining. Of course, it never pays to keep your head in the sand over business. Yet automatically tempering good news with a dose of pessimism is often applauded in the trucking industry.

But, as noted, the mood inside this show was nearly upbeat enough to turn the most dour prophet of doom into an optimist heady over the industry's bright future.

Certainly, all the suppliers we spoke to in Louisville were high on trucking in '98. No manufacturers sounded this theme more lustily than the contingent of truck builders on hand.

For example, Nick Panza, general manager of Peterbilt Motors, recounted how he recently informed some of the OEM's sales personnel that this was no time to wax nostalgic about the days when trucking was smaller and simpler. "I told them straight out," he said. "These are the good old days -- enjoy them!'"

And why not? During the show, OEMs offered forecasts of 1998 Class 8 retail sales (U.S. and Canada) ranging from 215,000 to 248,000 units.

Panza said the main drivers of the confident outlook are low inflation and interest rates, relatively stable fuel prices, and a boom in construction.

Whereas in the past OEM chiefs might have credited higher sales to pent-up replacement demand, Panza said that many Pete customers are both upgrading their fleets with the latest equipment -- and adding new trucks to handle more business.

Oh yeah, the rain's got to come sometime. There was at least one pesky cloud darting against all those sunshiny numbers. Several OEM chiefs commented that their suppliers must do more if truck builders are to break free of the "capacity constraints" threatening further production increases.

For their part, many supplier executives countered that the problem can't be solved simply by throwing more bricks and mortar at it. They say the root of the evil now bedeviling trucking runs back to when the American Rust Belt was being scrapped.

This scenario holds that when smokestack industries -- especially foundries -- were unceremoniously shipped overseas where work could be done more cheaply, no one foresaw the global demand that now exists.

So, U.S. manufacturers have to stand in line for what used to be forged in their own backyards. Not to mention they have to wait longer for all those overseas deliveries.

I'd venture to guess the thorny issue of capacity constraints won't get solved overnight or in a few sound bites. But getting back to our sunny theme, I am sure that if there's money to be made making more trucks and all the stuff that goes on them, more than a few industry leaders will soon stop throwing bricks and start building factories with them again.

Indeed, the truly cockeyed optimist spots opportunity a mile away. Even as OEMs await the goods to ratchet up production, they have their eye on what's over the horizon.

Once truck sales stop surging ever higher -- which may finally happen after the presidential election in 2000 -- OEMs will have to sell something else to take up the slack.

Why wait? Truck makers at the show were hot to trot out their latest service innovations -- everything from pre-engineered specs to branded credit cards.

The challenge to their fellow OEMs and to other aftermarket parts-and service channels was implicit: Get out of the way or get run over. That should give fleet managers something to smile about. The greater the competition for your business, the greater the price and service advantage you'll enjoy.