With state officials still undecided on the best way to rebuild the Massachusetts Turnpike through Allston, the Department of Transportation on Tuesday announced plans to spend $75 million repairing the elevated section of the highway in the near-term.

By most measures, that amount would represent a significant transportation project. But in this case, it’s a small sum compared to the enormous proposal that has long been debated on the same stretch of road.

The $1.3 billion megaproject to reshape Boston’s western edge would eliminate the large curve in the highway as it veers west toward Brighton, build a rail and bus station along the Worcester/Framingham commuter line, open up acres of development for a new neighborhood on land owned by Harvard University, and — depending on the state’s final decision — either bring the highway down to ground level, or build a new highway viaduct to replace the current one, that is nearing 60 years old.

Officials and advocates have for years tussled over how to best arrange these eight interstate auto lanes, four-lane Soldiers Field Road, a bike and pedestrian path, and the four sets of rail tracks through a narrow area that lies between Boston University and the Charles River. As the debate has stretched on, the state has argued that there is an increasingly urgent need to address the aging viaduct before it is declared too decrepit for large freight trucks.

The debate over the larger project is going to continue at least another few months, the state said Tuesday. But in the meantime, MassDOT said it is now planning steel and concrete repairs on the existing viaduct, arguing that they are needed soon — regardless of how the long-term plan is settled.

“MassDOT is ensuring the near-term safety of the viaduct and reducing the risk of future emergency repairs that would impact rail and road users,” the department said in a statement.

Although it is a new plan, the state pitched it as a “first phase” of the larger project. Last year, former Transportation Secretary Stephanie Pollack suggested that a smaller-scale repair job could delay the overall project by several years.

The $75 million in repair work, which will require approval from the transportation department’s board of directors, would likely take up to two years, though the state said it would have a limited impact on motorists because it will be focused mostly on the underside of the viaduct. It could begin in 2023, according to the statement.

Also Tuesday, the state said it would begin looking for a location for a new commuter rail repair facility, which is considered important for the larger project because a nearby bridge that connect the rail cars to the current facility could be forced offline during chunks of construction.

The moves mark the latest twist for a proposal that was once discussed as a much simpler plan to replace the old viaduct with a new one while adding the commuter rail stop, but has been through seemingly endless revisions amid widespread community debate.

Officials once thought the highway project would begin in 2017; whenever it does begin, it will take several years to build. And that will first require officials to arrive at a final decision about the configuration of all the infrastructure, and receive permits from multiple state and federal agencies.

A wide cross-section of business, educational, environmental, and neighborhood groups have called for everything to be squeezed at grade level, because it would remove the hulking viaduct as an eyesore and allow pedestrian bridges that more easily connect that part of Boston with the riverfront.

But the state has indicated a general preference for keeping the highway elevated, in large part because officials worry that any construction in or over the Charles River would struggle to get permits.

Meanwhile, the Charles River Watershed Association, an interest group dedicated to the river, has called for a different solution: to eliminate some auto lanes from the project, allowing everything to be built at grade without requiring any impact on the Charles. The state has refused to entertain that concept.

Reaction among some of the project’s many stakeholders was mixed Tuesday. Rick Dimino, president of the business-backed organization A Better City and a yearslong advocate for lowering the highway, said he welcomes the latest move, calling the $75 million in repairs a “down payment” on the larger concept.

But he stressed that the state still must commit to eventually grounding the highway, and wished officials had outlined a clear timeline for getting that plan finalized, permitted, and built — especially with Congress set to take up infrastructure funding soon.

“Having a design and construction schedule that’s shortened to take advantage [of a potential federal infrastructure bill] is critically important,” he said.

Meanwhile, Stacy Thompson, director of the Boston advocacy organization Livable Streets Alliance, lamented that the state had let so much time pass without reaching a decision that it had to take up an expensive short-term measure.

“The state must commit to grounding the viaduct,” she said. “There is consensus, and the state has backed itself into a corner, and as a result they are now going to put MetroWest through two different construction phases and waste taxpayer dollars. It’s unfortunate. . . . We just added $75 million to the price tag.”