But watch your luggage in stations, especially for the old switch racket, in which the operator substitutes a bag resembling yours, stuffed with old telephone books, for your own valuable belongings. At this writing, liquor is not sold or served to stock passengers on domestic planes except Northwest Airlines and it is against rules to tote your own hip pocket flask to drink while aloft. But no one cares if you do. Most through trains carry club cars, in which excellent hooch is sold at moderate prices. Liquor is not sold in club cars or diners while traveling through dry states (such as Kansas) or on Sunday in many wet states (such as Pennsylvania, Ohio and Indiana). If you can't do without your firewater, consult the ticket agent before boarding the train. Most club cars stop serving at 11 P.M., but if you tip the porter he'll provide you in advance with sufficient individual drink bottles and set-ups to keep you happy all the way. Club cars, incidentally, are the only ones in which you can meet people on de luxe trains. If you fancy a gal sitting in one, etiquette permits you to offer a drink. Dolls who don't want such overtures shouldn't sit in club cars alone. Of all travelers, the bus passenger finds himself at once in the most congenial crowd and the most uncomfortable surroundings. But, for the young or the adventurous, it holds prospects seldom found in planes or trains. Before you've gone 100 miles you are addressing the person next to you by the first name. If it should be an overnight trip, and she is cute and young, the odds are you'll be cuddling to keep warm after the lights are dimmed and the others drop off. If it's a two-day trip, you'll be engaged to marry before you reach the Hudson, and probably will have to. The experts on such things tell us you find the prettiest girls (and handsomest men) on buses. The dolls from the far, small places, who come to Gotham for gold and glory, to be chorines or models, seldom have more than a few dollars, which must be stretched to the limit. The bus is the economy way. Joe Russell, a New York press agent, has achieved some local fame for usually being the first to escort the latest young innocent beaut in town. We investigated to find out how he got them and learned that he made a practice of haunting the bus terminals and talking to the pretty ones who alighted. He asked them if they came to get in show business and usually got an affirmative answer. Then he offered to help them, and sometimes did, but not before he had a chance to show them off before the wolves at the hot spots. Many of these gals advanced; a few are stars. When the others discovered his racket, some of them, too, began haunting bus stations. Our enterprising friend again jumped the gun.