Metro-North Railroad has launched a full-scale attack on one of its biggest foes: autumn leaves.

When wet, slippery leaves fall on the tracks, they prevent the train's wheels from gaining traction, which damages them. So the railroad assembled a team of employees to come up with solutions.

The two-year study produced a brochure that was distributed to railroad workers last month informing train engineers and conductors how to pre-empt slip-slide -- when wet leaves build up underneath rail car wheels, making it difficult to brake and ultimately flattening the wheels.

"We felt we needed to establish a systemwide approach to a systemwide problem," said Dave Schanoes, deputy chief of operations for Metro-North's Hudson Line. "Rather than have engineers wait four or five years for them to gain the expertise," the study recommends employees learn what conditions cause slip-slide.

The slip-slide season usually is October to Thanksgiving and particularly affects tracks near Port Chester, N.Y., Greenwich and the New Canaan branch, Schanoes said.

Slip-slide problems often are caused by two conflicting safety mechanisms programmed into the rail cars.

When a train hits a buildup of leaves, the axles stop rotating and sensors trigger a release of the brakes so cars can slide to a stop. But if the train enters a speed restriction zone, that safety mechanism overrides the brake release, forcing cars to stop and flattening their metal wheels, Schanoes said.

Oils pressed out of the leaves trapped under the wheels make the wheels glide. As they do, they grind against the rails and wear away, and the wheels become squared. When this happens, riders can hear the squared wheels thumping against the rails.

To prevent that, railroad officials are telling employees where to expect leaf buildup and how it may affect speed restriction zones, Schanoes said. New employees are being taught braking techniques to avoid slip-slide.

Once the problem areas are identified, the railroad will dispatch equipment to clean the rails, Schanoes said. One machine, dubbed "Waterworld," is a washer set on a flatbed rail car that uses a high-pressure pump to blast water at 10,000 pounds per square inch -- enough to blow through a plank of wood.

So far, the employee education campaign seems to be working, Schanoes said.

In 2003, when the group started its study, there were 308 train delays systemwide related to slip-slide. Last year that number dropped to 150. For the first half of leaf season this year, the number is 46.

But the railroad hesitates to deem the problem solved.

"Conditions have improved, but we hate to take credit for it yet," Schanoes said. "Nature has a way of humbling us sometimes."