The inability to find specialized welders to retrofit too-wide rail track crossings to close the gap between too-narrow train wheels will delay the handover of the troubled rail project to the city for testing, which was supposed to happen by end of the year.

How much of a delay hinges on finding qualified welders on the mainland or perhaps outside of the country.

The half-inch gap between the rail trains’ wheels and X-shaped track crossings, called “frogs,” currently forces the automated trains to slow to 5 mph from 55 mph at the frogs, preventing the trains from operating on a schedule of station arrivals slated for every four to five minutes.

So the current plan is to add temporary welds to the frogs to close the gap until new, wider wheels are designed, manufactured, imported and installed. The first wider wheels on the first trains are hoped to be installed sometime in August, Nathaniel “Nate” Meddings, the rail project’s director of project controls, told the Honolulu Authority for Rapid Transportation board on Tuesday.

Previously, the aim was to have the manganese welding work begin on the frogs by mid-November to accommodate the existing narrower wheels. But no one is qualified in Hawaii, and no one else with the proper license has come forward to train local welders. HART’s bid solicitation to fix the wheel and track problems was issued in July.

“So it’s very, very likely that we will not be hitting that mid-month with the start of the weld fix,” Meddings said. “Obviously, that’s going to impact being ready for trial running at the beginning of the year. Hopefully, in a few weeks we’ll know … our path forward with bringing on qualified welders. … It’s kind of up in the air right now to identify who is going to do that weld fix. But it’s safe to assume that we’re not going to meet that mid-November schedule to start that weld fix.”

The welding work is designed as a temporary fix for the frogs to accommodate both the existing, narrower wheels and the eventual wider ones, Meddings said. But testing will have to be done to make sure both wheels will fit before handing the project over to the city’s Department of Transportation Services for city tests of the first leg from East Kapolei to Aloha Stadium, he said.

The temporary welds eventually will disappear from wear and tear from the wider wheels, and specialized welders will need to be available for long-term track repairs and maintenance, he said.

Hitachi Rail Honolulu, in the meantime, continues to work on designs for wider wheels and Meddings said the hope is to get the first sets on-island by August and the first seven trains all retro­fitted within a year “for the full fleet of new wheels.”

HART board chairwoman Colleen Hanabusa asked Meddings who will bear the cost to fix the mismatch between too-narrow wheels on too-wide frogs. In response, Meddings said while the matter of liability remains murky, HART administrators and Hitachi Rail Honolulu are “working in spirit of partnership” to get the trains running as intended.

“We’re saving the arguments over commercial liability until after we get the issue resolved,” he said. “But that is a big question. … Right now everybody’s goal, including DTS (the city’s Department of Transportation Services), the stakeholders is to get to opening. And that’s what we’re focused on.”

The current plan is to run a system comprised of 20 trains along a 20.2-mile, 21-station route from East Kapolei to the interior of Ala Moana Center, the state’s largest transit hub.

The project is currently budgeted at $12.499 billion and is not scheduled for completion until March 2031. The budget faces a current shortfall of about $3.5 billion, with no simple plan to plug the deficit.

The HART board has asked the City Council for an unspecified share of a new, proposed county Transient Accommodations Tax aimed at tourists — if the Council should approve the idea.