BANGKOK, Thailand (AP) _ A speeding passenger train derailed and most of its cars plunged into a ravine in northern Thailand, killing eight people and seriously injuring 59, officials said today.

The train was traveling Tuesday night at 47 mph hour as it took a hillside curve. It should have been going less than 30 mph, said Phairot Rotjalermngam, public relations chief for State Railways of Thailand.

Thirteen of the train's 15 cars derailed, he said. The accident occurred in Phrae province, about 300 miles north of Bangkok. Soldiers were helping pull the wreckage out of the ravine today.

State Railways officials said the Bangkok-bound express was traveling from the northern city of Chiang Mai, about 80 miles northwest of Phrae.

Eight people were killed and 59 were hospitalized, Amporn Larnlua, the railway's general manager for administration, told a news conference.

Another railways official said the driver and conductor were among those killed.

People from Australia, the Netherlands, Singapore and Malaysia were among those reported hurt.

Stephen Larter, 29, and his girlfriend, Karen Hewitt, 24, both of Brisbane, Australia, were among those slightly hurt.

In telephone interviews, Larter and Miss Hewitt said their rail car was thrown into the ravine when the fast-moving train derailed.

''I felt a crunch, and then the carriage rolled and people just flew,'' said Miss Hewitt. ''I ended up sitting on a fan on the roof, and there were people underneath me.''

She said three rail cars piled on top of each other, trapping many passengers.

''It was horrific,'' she said.

Larter said it was two hours before rescue teams arrived at the thickly forested area.

The Chiang Mai-Bangkok train is usually packed with passengers and is often taken by foreign tourists.

Chiang Mai is known for its hill people, trekking routes and the nearby ''Golden Triangle,'' where the borders of Thailand, Burma and Laos converge. It is one of the world's major opium growing areas.

Thailand's last serious train accident was in May 1988, when a truck rammed into a train in Nakhon Sawan province 130 miles north of Bangkok, killing 21 people.