We chose Moosonee because it's the nearer of only two spots on Hudson's and James Bay accessible by rail. (The other railhead, Churchill, Manitoba, is located directly on a spring-fall polar bear migration route.) There are a dozen other settlements around Hudson's Bay, but most of the year they're accessible by small charter aircraft only, and air travel's expensive in those parts. (In summer, there is ferry service on Hudson's Bay.)

GETTING THERE: The Polar Bear Express Cochrane-Moosonee round trip is $28.50 for adults, $14.25 for children. Reservations are necessary; one class of service fits all. During the late June to early September tour season, the PBE leaves Cochrane every morning except Friday at 8:30 and arrives in Moosonee at 12:50 p.m.; the southbound pulls out of Moosonee at 5:15 p.m., reaching Cochrane at 9:20 p.m. After the tour season, the PBE makes the round trip three times a week.

ALTERNATIVES: Air service to Moosonee serves primarily hunters and fisherfolk who'll pay practically anything to net that walleye or muskellunge. If you're a high roller in a hurry, you can get to Moosonee via Austin Airways Ltd., at the Timmins, Ontario, Airport, (705) 264-9521. Austin also flies to other James and southern Hudson's Bay hotspots, such as Fort Albany, Attawapiskat and Winisk. NorOntair, (705) 472-4500, has regular air service from Sudbury, Ontario, to Timmins. From Ottawa or Toronto, you fly to Sudbury via Air Canada, (416) 925-2311. They'll make connections for NorOntair and Austin or Voyageur Airways, (705) 675-1515.

Real thrillseekers can white-water canoe the 200 miles north on the Abitibi and Moose Rivers from the Cochrane vicinity all the way to Moosonee. There are hydro dams, so portages will be necessary. There are black flies, mosquitoes, deer flies and "no-see-ums," so Muskol or Old Woodsman's Fly Dope will be necessary. (For mid-route resupply, try Patrick Henry at Abitibi Outfitters, Smooth Rock Falls, Ontario, 705-338-4544.)

TOUR PACKAGES: Ontario Northlands Railway offers six guided package tours to Moosonee on its Polar Bear Express -- no high heels, please. You join the tour train in either Toronto or North Bay, all prices slightly lower from North Bay. From Toronto, an overnight stay in Iroquois Falls and a one-day round trip to Moosonee, with a ferry or Indian canoe tour to Moose Factory, starts at $270 if you're trekking solo. If you manage to rope others along, the per-person price plunges to $211 for a foursome. Children younger than 12 go for $105. All prices are in Candian currency and refer only to package No. 1 -- the three-day, two-night tour.

The same package, but with an overnight stay in Moosonee at the Polar Bear Inn or Moosonee Lodge, ranges from a loner's $340 to a trio's per-person of $264, the under-12 set paying $121. This package also throws in a wilderness excursion by the ferry Polar Princess from Moosonee.

Package tour reservations can be made with the ONR Toronto office, Union Station, 65 Front St. West, Toronto, Ontario M5J 1E6, (416) 965-4268.