A partially completed tower and a finished tower are seen in a section of the NECEC corridor along Route 201 in Bingham last November. The project has been stalled while legal challenges play out in court. Gregory Rec/Staff Photographer

A judge has tentatively scheduled an April trial in a lawsuit over the stalled New England power corridor that would bring hydroelectricity from Quebec through Maine to Massachusetts consumers.

Cumberland County District Court Judge Michael Duddy met Monday with lawyers for New England Clean Energy Connect, which wants to build a $1 billion, 145-mile transmission line from Canada to Lewiston, where it would connect with the New England electric grid. The judge also heard from lawyers for the state, who argue that a referendum approved by voters last fall blocks further work on the transmission line. Duddy issued the scheduling order following the meeting with the lawyers.

On Aug. 30, the Maine Supreme Judicial Court ruled that a referendum to block the transmission line would be unconstitutional if the work NECEC has already done on the project was enough to give the contractor “vested rights” in it before the voters had their say. If the lower court finds NECEC had established those rights, the project would be allowed to resume under the terms of the ruling.

The Supreme Judicial Court’s decision was seen as a partial victory for NECEC, which is spearheaded by Avangrid Inc., the Connecticut-based parent of Central Maine Power Co. But opponents of the project also claimed victory, saying the decision means the issue could be tied up in court for another year and that any delays are to their benefit.

The project is being paid for by Massachusetts utilities and their customers. But there have been years of delay and it’s not clear how long the Massachusetts utilities will be willing to foot the bills, with construction not yet a sure thing.

In his ruling Monday, Duddy said he wants each side to give him a list of any expert witnesses by November and a list of rebuttal witnesses by the end of December. The discovery process of compiling documents and other evidence must be complete by early February. Duddy plans to call both sides together again in March to set the details of the trial, which would begin the following month barring any delays that arise in the interim.

NECEC filed a court challenge to the referendum the day after it passed last November and continued work on the transmission line until executives were persuaded by Gov. Janet Mills to stop the work. In addition, the Maine Department of Environmental Protection suspended the project’s construction license on Nov. 23, and a judge in December turned down Avangrid’s request for an injunction to keep the referendum-adopted law from taking effect.

The Supreme Judicial Court has not yet ruled on a second legal challenge to the project, alleging that NECEC does not have a valid lease for a section of the transmission line near The Forks. Opponents of the project claim the lease wasn’t properly negotiated, and that the Bureau of Public Lands failed to determine whether the lease would lead to a “substantial change” to state lands that would require approval of two-thirds of the state Legislature.

Oral arguments on the lease case were heard by the Supreme Judicial Court in May, at the same time NECEC’s challenge to the referendum was heard. It’s not clear when the court might rule on that issue.