MOSS LANDING -- A picturesque stretch of rail line through Elkhorn Slough turned deadly Saturday afternoon when an Amtrak train slammed into a small pickup truck at a crossing at the entrance to a popular park.

A man and a woman in the pickup died instantly when the vehicle was hit by the southbound passenger train going about 50 mph, California Highway Patrol officers said.

The identities of the victims were not immediately released, but the CHP said they were both from Fresno. The male driver was 48 and his female passenger was 50, officers said.

The crumpled wreckage of the pickup came to rest about 75 yards south of the entrance to Kirby Park, below the elevated train track that straddles an arm of the huge estuary east of Moss Landing.

The train, which was carrying 150 passengers, was delayed for about 90 minutes after the 1:15 p.m. collision.

A witness told officers that the pickup was moving through the crossing when the train hit it, CHP Sgt. Wayne Disalvo said.

He said it wasn't clear whether the driver of the pickup was trying to beat the train at the crossing or simply didn't see it. He said he didn't know if alcohol was involved.

Some alcohol containers were thrown from the truck, but they could have been old, he said.

"We're looking at several scenarios," Disalvo said.

The crossing leads into the parking lot at Kirby Park, a day park with hiking trails and a small boat launch. Slough waters are on both sides of the railroad track.

The crossing to the parking lot is marked with black-and-white railroad crossing signs, a stop sign in both English and Spanish and another homemade stop sign.

No one on the train was hurt in the collision, Disalvo said.

An Amtrak spokesman said there was slight damage to the train, but not enough to prevent it from resuming its trip to Los Angeles. The train chugged away from the accident scene about 2:45 p.m.

Disalvo said he wasn't aware of any previous accidents at the crossing, but didn't rule out the possibility.

One man, who asked not to be identified, watched the knot of emergency vehicles beside the railroad track, shook his head and said, "It's terrible."

The man, who frequently walks at the park, said a warning light and guard bar at the crossing would improve safety.

"It's a small park, but there is a lot of traffic," he said.

A crane towered above the scene in a construction yard on the west side of the track -- the staging area for a construction project that started in November to install an underwater wall to slow slough erosion. The park is the property of the Moss Landing Harbor District.