As it has almost every year for more than six decades, the venerable S.S. Badger is again ferrying passengers, cars, and cargo across Lake Michigan this summer. But it's a different ship now.

Passengers shouldn't notice the changes. The beloved horns sound the same, the staterooms remain comfortable enough for a nap during the four-hour crossing, the TV lounges and restaurants are open for business. The large steamship, which is the last coal-burner on the Great Lakes and in the United States, retains its throwback grandeur.

What's missing is some of the ship's pollution. The Badger is sailing this summer season with a $1.2 million, high-tech combustion-control system that reduces the amount of coal it needs for the crossing. It also