A broken axle led to the May 5 derailment of a roller coaster at the Expoland amusement park in Suita, Osaka Prefecture, which killed a woman and injured 19 other holidaymakers. Not only had there been a lack of safety consciousness on the part of the operator but also unclear legal stipulations concerning safety checks.
The operator, Expoland, usually disassembles roller coasters in January or February and uses ultrasonic and magnetic-wave devices to check for cracks in vehicle components. But this year, it postponed the regular checkup until May 15 or later — after Golden Week — on the grounds that no space was available for the procedure. With the large turnout expected during Golden Week, the operator's decision was untenable.
The axle, 40 cm long and about 5 cm in diameter, broke almost perpendicularly. The surfaces of the broken sections are almost flat, indicating the possibility of metal fatigue. The company had not changed the axle since first putting it to use in March 1992. Nor was the company aware of the axle's life span.