Washington ? Train accidents jumped 15 percent in the past three years, troubling federal rail safety experts who suspect lax maintenance may be a factor.

Derailments caused by faulty tracks suspected in last Thursday’s Amtrak Auto Train derailment in Florida are up especially sharply. That accident, coupled with the head-on fatal collision of two trains Tuesday in California, and pending plans to ship by rail most of the nation’s nuclear waste to Yucca Mountain, Nev., are focusing attention on rail safety.

According to federal figures analyzed by Knight Ridder Newspapers, the number of train derailments in 2001 was the highest since 1985.

Overall, 2001 was the worst safety year in at least a decade in 14 categories, including rear-end collisions, accidents caused by faulty equipment and crashes with cars. The year 2000 was the worst in five categories.

Dramatic increases in rail traffic help explain the recent rise in accidents, especially derailments, which are up 32 percent since 1998. But after adjusting for added traffic, derailments are still up sharply. Accidents a category that includes collisions, explosions, car crashes and other mishaps are up, too.

Deferred maintenance and cuts in the number of union rail maintenance workers are cited by industry insiders as reasons for the increases.

“The reality is that our forces are stretched pretty thin,” said Rick Inclima, director of safety for the Brotherhood of Maintenance Way Employees, a national union.

Charles Dettmann, executive vice president for safety of the Association of American Railroads, the industry’s Washington lobby, said workers are being replaced by high-tech sensors and equipment that do the job better.

He said most accidents are minor, occurring in side yards and at slow speeds. Statistics show, however, that accidents on main lines and at higher speeds in 2001 were the worst in a decade.