What’s $1.5 billion between friends? Or taxpayers?

The deficit for the city’s rail system, pegged just a few months ago at $3.5 billion, is now likely to be far lower, rail officials say — around $2 billion, possibly even less.

Deficit numbers are never simple math, based as they are on projected costs and revenues. Wednesday’s positive spin was predicated on some definites, including cost-cutting measures enacted by the Honolulu Authority for Rapid Transportation, and some revised guesses about both future costs and projected revenue, which comes largely from rail’s share of state taxes.

The comments from HART Chairwoman Colleen Hana­busa and interim CEO Lori Kahikina did slow the clown car of negativity that has been dominating rail news to date. You can’t blame them for trying to change the narrative. After headlines about ballooning costs and such serious gaffes as wheels that don’t fit tracks, this project can’t take more bad news.

Hanabusa dropped a little more encouraging information Wednesday on the Honolulu Star-Advertiser’s “Spotlight Hawaii” online conversation: Rail could be running from Kapolei to Aloha Stadium by the middle of next year. It wasn’t a promise — “I’d like to believe that some portion of the ridership is going to be able to take place sometime next year, maybe mid-year at the latest,” is how she put it — and she can’t promise, anyway, since the city, not HART, will decide when the trains roll. But it is a bit of a bright spot.

And yes, although this initial leg would end at the rusting hulk of the now-abandoned stadium, it will pass many other more useful stations. Imagine Black Friday 2022, with shoppers able to make a traffic-free commute to rail stations near Ka Makana Ali‘i in Kapolei and Pearlridge Center.

Of course, we’ve heard all this before, in some form or another. So, no, we aren’t naive. We are in search of a reasonable assessment.

It must be noted that the lower deficit number is based on HART receiving a good share of a new 3% county transient accommodations tax, which is only now moving through the City Council. Under the current proposal, rail would receive a third of the tax revenue for two years, then its share would permanently increase to half. That could add up to more than $40 million per year.

Taxpayers should not stand for that money going into the black hole that is the building of the rail system. Estimates have been so wrong for so long, our trust is strained, to say the least. Oahu has far too many cash needs to see tens of millions go the way of so many millions before — into a deepening money pit.

Hanabusa acknowledged that the burden of proof is on HART. “We have given the public, over a period of time, so many different numbers that the people are beginning to wonder if we know what we’re talking about,” she said. Followed later by, “Most people are saying, ‘Hey, we are not going to throw good money after bad, so you guys, HART, show us that this is doable,’ and I think that’s a highly reasonable position.”

Our Council members must hold HART to that. Not only must the agency show how it will use the cash to meet its shortfall, it must show how it is managing costs, guarding against further construction mistakes and holding its contractors accountable.

A more tenable use of that city tax revenue will come once rail is operating, to maintain the system and subsidize its daily operation. Public transit is seldom if ever sustained by ridership fees; these systems are a public service and require a steady income stream.

But once the trains are running, the people will be getting something back for their bucks.