TOKYO —  A roller coaster traveling up to 46 miles per hour hit a guardrail at an amusement park in western Japan on Saturday, killing one person and sending 34 others to hospitals, officials said.

An axle on one of the six cars broke, causing the accident at Expoland in Osaka, 255 miles west of Tokyo, Kyodo News agency reported.

It happened amid Japan's "Golden Week" holiday, when many families pack amusement parks and other tourist sites. Saturday was the Children's Day national holiday.

Osaka police official Kaoru Tanaka said a woman was killed. Fire department official Naokazu Norigami said 34 people were taken to hospitals. He said one person sustained a head injury but others were apparently not seriously hurt.

The park was closed following the accident, according to park official Kazuhiro Shiba.

The standup roller coaster could hold up to 24 passengers and travel as fast as 47 miles per hour, Shiba said.

"A fatal accident occurred on Children's Day, which was supposed to be a fun day. I am at a loss for words to express my apologies," Expoland president Saburo Yamada told a news conference in Osaka.

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Expoland opened as the amusement zone for the 1970 International Exposition held in Osaka.