Federal investigators said Thursday that they expect to issue a preliminary report in about two weeks on the fiery collision between a commuter train and an SUV that killed six people in the New York City suburbs.

Eric Weiss, spokesman for the National Transportation Safety Board, said the report should be out the week of Feb. 23.

Such preliminary reports from the NTSB rarely include major disclosures or conclusions. Those could be several months away.

A Metro-North Railroad train that had just left Grand Central Terminal crashed into a Mercedes SUV on Feb. 3 at a grade crossing in Valhalla, sparking an explosion and fire that burned out the first car of the train and sent pieces of third rail stabbing through the passenger area. The woman driving the SUV and five men on the train were killed.

NTSB investigators began arriving the next day and stayed until Wednesday, Weiss said. At times there were more than a dozen investigators at the scene, he said.

The NTSB held three briefings near the scene last week. Weiss said they do not plan to comment again on any findings before issuing the preliminary report.

The board has said these are among its key questions:

— Why the SUV driver was on the tracks; one witness told the investigators the SUV was hit by the dropping crossing gate and the driver then moved forward and was hit by the train.

— Why the railroad’s third rail came up in pieces, piercing both the SUV and the rail car.

— How the victims were killed; a medical examiner said all suffered both burns and blunt-force injuries but did not specify a cause of death.

— Whether the third rail’s unusual design, meant to protect it from snow, contributed to its breaking up.

(AP)