The city’s troubled rail project and its skyrocketing price tag dominated conversations across Oahu during 2016, from the neighborhood Zippy’s coffee hour to the political debates of Honolulu mayoral candidates.

The saga topped the list of this year’s biggest stories for Hawaii.

1. Rising cost of rail

The latest financial plan indicates the overall cost could hit $9.5 billion — or nearly $3 billion more than what Honolulu Authority for Rail Transportation officials were forecasting when 2016 began.

With costs escalating, politicians and the public demanded changes within HART, and they got them: Chairman Don Horner resigned in April, and Executive Director Dan Grabauskas left in August, among other changes.

On the campaign trail, incumbent Mayor Kirk Caldwell and challengers Charles Djou and Peter Carlisle spent much of the summer sparring over how much the current administration is to blame for the project’s soaring costs.

In December the Federal Transit Administration agreed to give the city until April 30 to submit a plan for how it would make up the shortfall for the largest public works project in the state’s history.

2. Pearl Harbor anniversary

The commemoration ceremonies surrounding the 75th anniversary of the attack on Pearl Harbor were done up big, honoring the heroes of that day of infamy, among others, during 11 days of memorials and events.

The event drew thousands to Hawaii, including dozens of survivors in their mid-90s for what was billed as a likely last opportunity to remember that pivotal moment in American history.

About 5,000 people attended the Dec. 7 remembrance ceremony, but there were many other solemn events, including memorials dedicated to the USS Utah and USS Oklahoma and the reconciliation “Blackened Canteen Ceremony” at the USS Arizona Memorial.

A few weeks later, on Tuesday, President Barack Obama and Japanese Prime Minister Shinzo Abe met at the Arizona Memorial in a landmark display of reconciliation.

3. Billy Kenoi’s trial

Popular Hawaii County Mayor Billy Kenoi faced a potential prison term for misusing his county purchasing card, or pCard, over a four-year period, but a Big Island jury found him not guilty of all charges following a two-week trial.

Kenoi, who made more than $129,000 in charges on his pCard while in office, subsequently reimbursed the county for at least $31,000 in personal charges, including trips to Honolulu hostess bars.

Less than two weeks after he was acquitted, Kenoi admitted that there was probable cause he violated the county’s ethics code. The admission was part of an agreement with the Hawaii County Board of Ethics that allowed Kenoi to dodge an investigative hearing and to close the matter.

Kenoi ended his eight years as mayor in December, replaced by former Mayor Harry Kim, who campaigned on, among other things, returning integrity to the office.

4. Marines die when helicopters crash

The year started in tragedy when 12 Hawaii Marines were killed Jan. 14 as two CH-53E Super Stallion helicopters collided off Oahu’s North Shore on a night training mission.

The impact at 1,500 feet elevation caused an explosion that instantly killed all aboard, according to a crash investigation report that cited pilot error as the primary cause.

But there were serious contributing factors, the report noted, including the “appalling” state of the unit’s fleet of helicopters, a situation that prevented the pilots from getting enough flying time and training to maintain readiness and proficiency.

Naval Air Systems Command announced in August that the Marine Corps was overhauling its CH-53E helicopters in a move to significantly increase the number of operationally fit aircraft and address “systemic issues.”

5. Outbreak of hepatitis A

Hawaii experienced the worst outbreak of hepatitis A in at least a quarter-century when 291 people came down with the contagious liver disease. Seventy-three people were hospitalized, and at least one eventually died of complications that may have been related to the illness.

State health officials first alerted the public to a cluster of cases on July 1. A month and a half later, they shut down Genki Sushi restaurants on Oahu and Kauai for one month after discovering that the source of the outbreak was raw scallops imported from the Philippines.

The outbreak resulted in a couple of class-action lawsuits against Genki Sushi and at least one other suit from a man who claimed he caught the virus aboard a Hawaiian Airlines flight.

In April state officials declared the end of a dengue fever outbreak, which had sickened 264 Big Island residents going back to September 2015.

Star-Advertiser reporter Gordon Pang contributed to this report.