COOL your heels on the rail of an observation car. Let the engineer open her up for ninety miles an hour. Take in the prairie right and left, rolling land and new hay crops, swaths of new hay laid in the sun. A gray village flecks by and the horses hitched in front of the post-office never blink an eye. A barnyard and fifteen Holstein cows, dabs of white on a black wall map, never blink an eye. A signalman in a tower, the outpost of Kansas City, keeps his place at a window with the serenity of a bronze statue on a dark night when lovers pass whispering.