TORONTO -- The long-delayed inquest into the prison death of a deeply troubled teenager finally appeared to be on track Tuesday amid unprecedented signs of co-operation by prison authorities and doctors who had been fighting tooth and nail to limit their exposure.

Instead of the legal wrangling that has become the defining hallmark of the probe into the death of Ashley Smith, the parties spent a few hours in rare agreement before proceedings were adjourned until the new year.

Richard Macklin, a lawyer for Ontario's child and youth advocate, said Smith's family had been on a "litigation caravan" for two years that finally ended with the screening of disturbing jailhouse videos late last month.

"We're seeing the co-operation that flows from the shining a light on the videos relating to Ashley Smith," Macklin said.

"All of a sudden, when we finally succeed on the video issue, the house of cards collapses."

Among other things, the jailhouse videos showed authorities duct-taping a hooded, docile Smith to her airplane seat and injecting her against her will with tranquilizers.

Smith, 19, of Moncton, N.B., died in her cell at the Grand Valley Institution in Kitchener, Ont., in October 2007 after wrapping a strip of cloth around her neck. Guards who were ordered not to intervene stood watch outside her cell.

Most of her final year was spent in segregation being shunted 17 times among nine different prisons in five provinces.

Correctional Service Canada and four psychiatrists who treated Smith in institutions outside Ontario fought unsuccessfully to keep the videos under wraps as part of their motion to severely restrict the scope of the inquest under Dr. John Carlisle.

They argued Carlisle's authority ended at the Ontario border and that he had no right to delve into the federal prison system.

On Tuesday, Carlisle dismissed their motion to narrow the inquest scope, saying he would provide written reasons at a later date.

Lawyers credited the new-found harmony to the public outcry that followed the video screening and the intervention of Prime Minister Stephen Harper, who called prison authorities' treatment of Smith unacceptable and ordered them to co-operate with the inquest.

As a sign of the co-operation, the out-of-province doctors -- Jeffrey Penn, of Truro, N.S., Olajide Adelugba, of Saskatoon, Renee Fugere, and Michelle Roy, both of Montreal -- agreed to give evidence voluntarily.

Mark Freiman, who speaks for the doctors, said his clients had not withdrawn their objections to the broader scope but would wait to see Carlisle's written reasons before deciding any next steps. He did say the doctors would testify.

"The doctors have agreed voluntarily to attend and to assist and to produce any documents," Freiman said.

"We've always believed that an interprovincial subpoena was not necessary."

Carlisle adjourned the inquest until Jan. 14, when it should finally be set to hear evidence.

This is the second inquest into Smith's death. The first collapsed last year amid legal wrangling and hostility when the presiding coroner, Dr. Bonita Porter, retired suddenly.

Other parties expressed cautious optimism the inquest would now finally get going in January as scheduled.

Howard Rubel, who speaks for the Union of Canadian Correctional Officers, said guards had been waiting for years to get the inquest moving and said it appeared that would now happen.

Before adjourning, Carlisle ordered Corrections to produce a list of relevant videos in its possession and to turn over any it hadn't already done so.

"We've been chasing videos for close to three years now," Breese Davies, who speaks for the Canadian Association of Elizabeth Fry Societies, told the coroner.

"We don't have time to be chasing after materials any more."