Tokyo subway operator Teito Rapid Transit Authority on Monday announced a set of new safety measures to prevent derailment, worked out in accordance with a recent Transport Ministry panel report urging the operator to strictly manage wheel load balance.

Teito said it has already corrected the imbalance of all cars to less than 15 percent and will achieve 10 percent, as proposed by the report, by the end of fiscal 2001.

The report was written after a derailment on Tokyo's Hibiya Line in March that killed five and injured another 63.

Teito also admitted that it lacked a system to study and learn from accidents involving other railway operators, having become overconfident of its safety record with no fatal accidents in its nearly 70-year history.

Some Teito engineers had privately acquired information on a 1986 derailment accident of Tokyu Corp. that concluded load balance management is essential to preventing derailment. But Teito never gave the conclusion serious thought until after the March accident.