Dramatically transforming sections of the Long Island Rail Road that require diesel instead of electric railcars — speeding up commutes and expanding ridership — has for decades been a goal of Island officials.

A new report says it has found a far cheaper way to do it: switching to overhead lines, rather than building a traditional third rail on the ground.

Still, even at the cheaper option, the price tag is estimated to be a daunting $13 billion, though it could be built in segments over time, according to the report from New York University's Marron Institute of Urban Management.

Metropolitan Transit Authority officials and experts questioned how realistic the proposal is, given that it would require an entirely new fleet of LIRR trains and additional maintenance costs.

The new approach to further electrifying the LIRR system, where trains operate throughout much of Suffolk County on diesel fuel, would involve an overhead catenary wire system. Tracks currently are electrified only as far as Ronkonkoma on the Main Line, Babylon on the Montauk line, and Huntington on the Port Jefferson line. A segment of the Oyster Bay line in Nassau County also is not electrified.

LIRR officials have said the high cost of electrifying tracks has limited their ability to improve and expand service in diesel territory.

The NYU study estimates a third rail would cost at least $49.2 million per mile. Using costs from other rail systems, the study estimated the overhead option would cost the LIRR between $11 million and $27 million per mile. That could shave $700 million off the cost of electrifying the Port Jefferson branch.

"The trains would run on the overhead wires until reaching the third rail network and then switch over," according to the study, which noted that the LIRR’s sister railroad, Metro-North, uses a similar operation on its New Haven line.

In a statement, MTA spokesperson Eugene Resnick said the transit authority welcomes ideas for "expanding Long Island Rail Road capacity cost-efficiently, and will review the report's recommendations."

Jamie Torres-Springer, president of construction and development for the MTA, noted that as part of its $68 billion 2025-29 capital budget, the MTA aims to expand capacity on the LIRR, potentially through further electrification of the rail system.

Yaphank electrification eyed 

The MTA aims to electrify its tracks another 11 miles to Yaphank, where the LIRR is building a new station near Brookhaven National Laboratory. The electrification of the Port Jefferson line, which has been high on the wish lists of Suffolk elected officials for years, is likely further away, as the MTA has said the project’s $3.1 billion price tag makes it cost prohibitive.

Addressing the proposal to use an overhead wire system on the LIRR, Torres-Springer said the MTA "will always look at all options," but noted there are advantages and disadvantages for different options.

"You may have lower up-front capital costs, but you have to buy new rolling stock [trains]. You have higher maintenance costs down the road," Torres-Springer said at a news conference earlier this month in Queens.

The study estimated "complete electrification of the LIRR system," plus other necessary infrastructure upgrades, would run between $11.9 billion and $12.9 billion. That does not include the cost of purchasing a train fleet that could run on both third rail and overhead wire power. Metro-North’s M8 model trains, which have that capability, cost about $5.4 million per car, according to the study.

'Dramatic' reductions in commute times

Nolan Hicks, who authored the study, said in an email that it roughly estimated 350 to 400 cars would be needed, but costs could be at least partially offset by needing fewer new diesel trains.

For the investment, the study said, commuters in diesel territory would see "dramatic" reductions in trip times: 20 minutes faster between Penn Station and Oyster Bay and 19 minutes faster between Penn and Port Jeff. The study says trains on overhead wires would be able to move even faster than those on the third rail.

LIRR Commuter Council chairman Gerard Bringmann said while the report’s proposal "seems fine in theory," the size, scope and cost of the required work make it "just unrealistic," especially given the uncertainty surrounding future federal funding for the MTA.

Hicks said it kept the MTA's financial condition "front of mind" and the project could be completed in segments over time.

"What this program does is turn a mega project into a series of bite-sized packages that allows the MTA to deliver a rolling program of improvements that will ... speed commutes and make trips easier for everyone on Long Island," Hicks said in an interview.

David Lester, editor-in-chief of Railway Track and Structures, an industry trade journal, said the MTA should "absolutely not" dismiss the report’s findings. Lester noted that several high speed rail systems throughout the world, including Amtrak’s Acela service, operates on overhead catenary wires, which come with several advantages, including conducting electricity more efficiently than a third rail, and being less vulnerable to flooding issues.

But Lester acknowledged that expecting the 191-year-old LIRR to consider such a major change is a big ask.

"I think there’s some inertia there," Lester said.