Elected officials say they are confident the deal reached by the Metropolitan Transportation Authority and the Related Cos. to develop the West Side rail yards would not suffer the same fate as the Tishman Speyer deal, which dissolved before the ink was given a chance to dry.

The tentative deal reached late Sunday night is valued at $1.054 billion — the same as the Tishman Speyer deal — and calls for Related to sign a 99-year ground lease with the MTA for the 26-acre rail yards. The MTA said it would use the proceeds of the lease to fill a $700 million hole in its capital budget.

Related and its financial partner, Goldman Sachs, plan to develop 5.5 million square feet of commercial space, 1 million square feet of retail space, a hotel, and 5.3 million square feet of residential space. The plan also includes 440 units of permanent “affordable” housing, an aspect that could help the plan gain local support and the necessary approvals during the city’s land use review process.

“Despite the setbacks of the last few weeks, we are certain that Related and Goldman will realize this tremendous opportunity to develop what is really the only large parcel of undeveloped space left in Manhattan,” Mayor Bloomberg said yesterday in a statement.

Senator Schumer, who is taking a renewed interest in the development of the West Side, said in statement: “The MTA deserves credit for moving this project along and not allowing it to fester. The fact that developers are willing to put money in to this project shows that New York will certainly need more office space in the near future. It now makes it even more important that the 7-train extension is built and built on time.”

The district manager of Community Board 4, Robert Benfatto, said that of the original five proposals for the rail yards, Related’s came in second to last in polls of the surrounding neighbors. But he said the residential component of Related’s plan and its allocation of “affordable” housing would work in its favor.

“Related has done affordable housing work in the past, but the devil will be in the details. We will be seeking to reach out to the MTA and Related to meet with them soon,” he said.

In March, Related’s original bid suffered a blow when News Corp., which had signed on as a lead tenant, withdrew from the project. Now Related’s proposal lacks an anchor tenant. Real estate experts say anchor tenants provide financial stability and more certainty that the developer will follow through on such deals.

“We are confident that working closely with the visionary leadership of the State and City and the MTA, using the absolute best architectural, planning, engineering and construction talent, and having the financial strength and acumen of Related and Goldman Sachs, we will achieve our shared goals,” the chairman of Related, Stephen Ross, said in a statement.

Members of the development community said they were impressed with the MTA’s ability to reach a new tentative agreement with Related less than a week after Tishman Speyer backed away from the negotiating table last Tuesday. Some experts had suspected that Tishman’s concerns about obtaining assurance on the extension of the no. 7 subway line and rezoning would lower the value of the other bids. The two other remaining bidders were Extell Development Co. and a joint venture of the Durst Organization and Vornado Realty Trust.

“If the MTA was able to get close to the deal they had with Tishman — which they clearly did — then they were able to pull this one out,” the president of the Real Estate Board of New York, Steven Spinola, said.

A special meeting of the MTA board has been called for this Thursday to initiate the approval process.