Passenger rail lines have often poked their way into the world's remote outposts. And despite the competition from airlines, regular (and irregular) service still runs over many of the tracks. On some routes, you may encounter delays and discomfort, but the view from the window is always fascinating. Among the most unusual:

La Paz, Bolivia, to Arica, Chile: Down from the high Andes (at a maximum altitude of 14,000 feet) to Chile's northern desert at sea level. Lucky travelers will spot herds of llamas in the mountains. Infrequent departures; about 10 hours.

Bangkok to Chiang Mai, Thailand: North from the Thai capital through the lush, hilly countryside to the mountain resort city of Chiang Mai. Many views of village life. Fine trains with air-conditioned sleeping cars. About 12 hours.

Oslo to Stockholm via the Arctic Circle: North along the fiord-cut coast of Norway to Narvik in the Land of the Midnight Sun by train, bus and ferry; south again through the Swedish countryside to Stockholm. Excellent trains. With sightseeing stopovers, the trip should take about a week.

Across Hokkaido, Japan's northern island: A primitive region of mountains, forests and lakes, with the hot springs and ski resort city of Sapporo. Good trains. From Hakodate, at the island's southern tip, via Sapporo to Kushiro on the east coast is about nine hours.

Anchorage to Fairbanks via Mount McKinley: Magnificent Alaskan wilderness scenery and North America's highest mountain, viewed from a Vistadome car. About 9 1/2 hours.

Penang and Butterworth to Singapore via Kuala Lumpur: The names alone are exotic enough to warrant this trip down the Malaysian peninsula, but the glimpses of village and country life (and the water buffalos) will keep you at the window. Comfortable, air-conditioned cars. About 22 hours.