The city of Baltimore and CSX Transportation have agreed to split the cost of rebuilding the one-block retaining wall that collapsed along East 26th Street in Charles Village, ending months of negotiations over who was responsible and how much taxpayers would cover.

City officials said Monday they expect the collapse to cost taxpayers about $7.5 million — though the total could increase as construction continues — and CSX would pay the rest. The entire project is now expected to cost about $15 million, down from an initial estimate of $18.5 million.

The landslide amid heavy rains in April sent half the block of East 26th Street between St. Paul and North Charles streets tumbling into a cut of parallel railroad tracks owned by CSX. Residents of the block were displaced for weeks and still are living in a construction zone.

Responsibility for the repairs has been a touchy subject, as CSX and city property lines intersect across Baltimore, a city with aging infrastructure and active rail lines. While the city and CSX have split costs related to retaining walls around tracks in the past, some city leaders had expressed hope that the railroad would contribute more to the reconstruction this time around.

City Council President Bernard C. "Jack" Young said he was "disappointed" with the agreement. He said CSX "should have paid for it all," and that he believed the wall had been maintained by the railroad.

Councilman Carl Stokes, who represents the area, said he would "trust the wisdom of the city administration" if it believed the agreement helped avoid "long and lengthy litigation," but that he has never seen documents to show "who really is truly responsible."

Neither the city nor the Florida-based railroad accept responsibility for the collapse in the agreement, but release each other from liability. They also agree to split the cost of any losses or damages awarded to third parties who bring claims in relation to the incident, with the provision that legal restrictions on government liability would cap any city contribution.

"This is a complex and significant incident. It's not easy to determine causation," said David Ralph, the deputy city solicitor. "In fact, you know, neither party believes we're necessarily at fault for this, but we realize others might hold one or both of us responsible for something that was an act of God."

Kevin Harris, a spokesman for Mayor Stephanie Rawlings-Blake, said the mayor believes the agreement is "equitable and fair."

William Johnson, director of the city transportation department, said negotiations began soon after the collapse. "We didn't always agree on everything, but the one thing I give them credit for is they remained at the table," he said of CSX.

Johnson said he expects the project to be completed by the end of the year but called that "a very tentative estimate" given the amount of work that still needs to be done. He said a harsh or early winter could extend the timeline.

Bryan M. Rhode, regional vice president of state government affairs for CSX, said in a statement that the company is "pleased" to have reached a deal.

"The agreement is fair, and brings quick resolution to what otherwise could have been a protracted process. The agreement also establishes a foundation for an even stronger relationship between the City and CSX in the future," he said.

The agreement, released Monday, will go before the Board of Estimates on Wednesday. It covers construction costs, including those under a $12 million contract the city approved last month with contractor Concrete General.

In addition to half the construction costs, the city will cover the engineering work — expected to be about $1.5 million — and those costs associated with its emergency response and staffing needs. CSX will cover costs related to clearing the tracks of debris in the days following the collapse, and other costs.

The agreement also makes CSX responsible for the maintenance of the wall but does not block it from asserting city responsibility for future degradation of the wall, or from seeking reimbursement for that degradation. The parties also agreed to survey the wall once it is rebuilt to ensure city and CSX property lines in the area are clear.

Harris said the city has conducted a review of the incident, including an assessment of what likely caused the collapse, and is in the process of completing its report. He said Rawlings-Blake plans to meet with affected residents to go over the report with them.

"The mayor wants the opportunity to meet with the residents," Harris said.

Residents had complained of damage to the street for years before the collapse, and city officials in May 2013 had placed the street on a list of city roads needing full replacement.

After the collapse, residents criticized the city for not taking more immediate action to address the problems but also praised the city for acting quickly to put them up in hotels and help pay for unexpected transportation and food costs while away from home.