House lawmakers proposed Tuesday to spend $400 million to address safety issues at the MBTA and transportation advocates are now scrutinizing how the cash could be spent while the branch’s chief budget writer said the amount could fluctuate as discussions continue.

Lawmakers included the funding in a $10.4 billion infrastructure borrowing bill the House’s budget-writing committee advanced Tuesday and scheduled for floor debate Thursday. It aims to address what the Federal Transit Administration described as “continuous safety violations” at the MBTA in a series of preliminary findings from a safety inspection initiated in April.

The bill allocates money to the Department of Transportation to deal with “safety concerns related to the interim and final findings uncovered” during the FTA’s safety inspection and requires the MBTA to work with MassDOT and the Department of Public Utilities to plan any projects funded through the bill.

Rep. Aaron Michlewitz, the House’s chief budget writer, said the money was placed in the bill after conversations last week following the FTA’s preliminary findings and the MBTA announcing service cuts on the Red, Orange, and Blue Lines as a result of staffing challenges at the agency’s Operations Control Center.

Michlewitz said the House felt that the MBTA and Baker administration may need access to “some quick money” to address final recommendations from federal officials that are expected to be released later this summer.

“We haven’t been given a specific amount yet. I think that the $400 million was, again, seen as a placeholder. We expect that at some point, we’ll hear something from the FTA/MBTA on exactly what the financial impact of some of these safety questions or concerns may be about and so we may have further conversations on that,” the North End Democrat told MassLive.

But some transit advocates are worried the funding may not tackle a large portion of operational issues outlined by the FTA like staffing challenges at the Operations Control Center, which coordinates train movements across the system.

LivableStreets Alliance Executive Director Stacy Thompson said the $400 million could end up being used on a variety of capital, or long-term, projects at the MBTA instead of day-to-day expenses to bolster safety.

“The FTA actually called out explicitly in their preliminary reports that there has been an over-focus on capital and there has been a lack of focus on operating,” Thompson told MassLive. “And so there is nothing wrong with the $400 million, it’s a good investment, but it is not actually meaningfully or directly addressing any of the four recommendations that the FTA laid out. That is an operating question.”

Michlewtiz said the language in the bond bill was specific and pointed directly at addressing findings from the FTA.

“I think that that was something that we were particular on with the language but other than that, I think we don’t have a definitive response to something that we just don’t know exactly what we’re up against yet financially,” he said. “The bond money is no different than regular allocations in terms of its flexibility but we were very specific on that it had to be addressed to the FTA findings.”

The safety directives from federal transit regulators honed in on delays in critical track maintenance, the Operations Control Center, staffing, a lack of safety culture at the MBTA, and lapsed certifications for employees’ who need one to do their job.

MBTA spokesperson Joe Pesaturo deferred questions to the Legislature about how the money included in the House’s infrastructure bond bill could be spent.

“T staff is still reviewing the language,” Pesaturo said.

A spokesperson for MassDOT did not respond to a request for comment.

Auditor candidate and former head of Transportation for Massachusetts Chris Dempsey said delineations between capital and operational expenses often fall into a gray area but ultimately the Legislature can decide what it wants to do with the funding.

“There’s a whole bunch of things in the middle,” he said.

Thompson questioned whether MassDOT or the MBTA could use funds proposed by the House to hire more dispatchers, track employees’ certifications, or run recruiting campaigns to fill a number of open positions at the MBTA.

“I would want to know how much of that $400 million goes to hiring and paying for those people and my guess is probably zero,” Thompson said. “That is the question that I think the Legislature needs to address. I don’t want to dunk on this, it’s good they want to do something, but I don’t think that the public should believe that this solves the problem or that we’re putting more money where it’s needed most because we’re not, we need money on the operating side.”

Senate President Karen Spilka and Mariano earlier Tuesday scolded Gov. Charlie Baker for his management of the MBTA, and said they would hold a legislative oversight hearing to “restore public confidence” after the “alarming” discoveries by FTA officials.

Several hours later the House moved forward on a new version of the transportation bond bill that included the funding to address issues at the MBTA.

In a statement to MassLive, Baker spokeswoman Anisha Chakrabarti said the administration “supports the MBTA’s immediate actions to implement the FTA’s findings, including an aggressive hiring campaign to recruit more dispatchers.”

“The Administration shares the Legislature’s goal to make the T as safe as possible and has invested nearly $8 billion into new tracks, cars and signals to make up for decades of deferred maintenance by state government,” Chakrabarti said.

Former transportation secretary Jim Aloisi said the MBTA doesn’t need more legislative oversight when the FTA is already looking into safety issues at the agency.

“The Legislature needs to act ASAP to prevent a transit operating budget crisis next July,” he said on social media.

Dempsey said he applauds Spilka and Mariano for moving forward with an oversight hearing, and offered a “bravo to the House for including funding in the transportation bond bill to take a look at these issues and try to address them.”

“I hope that a significant share of the resources that are being allocated to the T are being put into oversight and assessment and improvement of culture, and not just into safety infrastructure,” Dempsey said. “This is not just an issue of sort of like technology or an issue of aging infrastructure, it also speaks to operational challenges and management and cultural challenges and we need to get to the root of those.”

Sen. Diana DiZoglio, a candidate for auditor, said investment of any kind into the MBTA is welcome, “but the MBTA’s safety issues require both additional investment and better oversight.”

“We need a long-term revenue stream and state leaders who will actually step up to ensure accountability for riders and workers alike,” she said. “We have had a failed transportation system and poor management for decades — and the status quo is just not good enough. We need a public transportation system that reliably, safely and properly serves the people of Massachusetts.”