Dallas Area Rapid Transit says it can afford to give both Dallas and its neighbors what they want: a subway downtown and an east-west rail line to the north.

But as pressure mounts for the agency to give preference to one over the other, DART is now considering five financial scenarios, including one with a shortened suburban rail.

The DART board will study these proposals at a meeting Tuesday in preparation for a vote on the agency's 20-year financial plan Oct. 25. The plan will define the scope and timeline of a second downtown rail line dubbed D2 that many want built as a subway and the long-delayed Cotton Belt corridor that would take riders from DFW International Airport to Plano.

These are the five scenarios under consideration:

Scenario 1: Presented on Aug. 9, it expedites the Cotton Belt's opening from 2035 to 2022 and slashes the price tag to $995 million. D2 would be half street-level and half tunnel (as originally approved by the Dallas City Council last year) and would cost $616 million. DART would seek $325 million in federal subsidies for the downtown project, which would open in 2021.

Scenario 2A: This plan introduced on Sept. 6 keeps the same assumptions as Scenario 1 but revises the cost of the Cotton Belt to $1.1 billion.

Scenario 2B: Also presented on Sept. 6, this plan includes a $1.1 billion Cotton Belt and bumps the cost of the downtown rail line to $1.3 billion so it can be built entirely as a subway. Downtown service would be delayed two years to 2023. It assumes that DART will double its federal grant request to $650 million for D2.

Scenario 3: Formally proposed Sept. 27, this plan would build D2 as a subway but develop only half of the Cotton Belt, from DFW Airport to Addison, skipping Dallas, Richardson and Plano. This would allow D2 to be built with only $325 million in federal subsidies, with a debut in 2023.

Scenario 4: Also proposed on Sept. 27, this scenario keeps dozens of projects pitched this year but reverts the D2 and Cotton Belt projects to their 2015 versions. That means no subway for downtown Dallas and a 13-year delay for the Cotton Belt. The version of the Cotton Belt corridor approved by DART last year has double tracks and more stations but costs $2.9 billion.

The DART proposal that rolls back development of the Cotton Belt follows requests from the board for more information. Some board members have criticized DART staff for focusing on the suburban project without presenting details about how the Cotton Belt could be phased in to devote more debt to a subway downtown.

Top executives at DART maintain that the agency can do both at the same time, as long as federal authorities disburse $650 million for D2. DART would take out about $1 billion in debt to pay for the Cotton Belt.

But some Dallas city leaders are skeptical and fear the Cotton Belt debt will jeopardize funding for the D2 project. The City Council's transportation committee is promoting a resolution that urges DART to prioritize the subway, improvements to bus service and a streetcar route downtown. Currently the bus overhaul in Dallas is expected to be rolled out over a 10-year period.

None of the five scenarios under consideration expedites changes to bus service. DART executive director Gary Thomas said just acquiring additional buses will take two years.

"The biggest opportunity is to get those buses ordered as quickly as we can," Thomas said. "We'll look at other components of the plan to see what we can accelerate, where we can move things up, certainly."

For some stakeholders, the scaled-back Cotton Belt proposal doesn't work.

Addison Mayor Todd Meier said that for DART to make good on its commitment to the city from 1983, that line needs to be built in full.

He said he also supports a second downtown rail line but suggested that Dallas pay for the cost to bring it underground.

"I don't think it's fair for the whole system and all the members of the system to subsidize what amounts to an aesthetic improvement of the system that benefits one member ... in this case being Dallas," Meier said.

The full Cotton Belt route from DFW International Airport to Plano

Dallas City Council member Philip Kingston doesn't view it that way. He said the D2 line should be prioritized because it would boost DART ridership and improve the health of the whole system.

"If the rest of the system isn't functioning, Cotton Belt is little more than decoration," Kingston said.

He noted that a phased Cotton Belt doesn't address his concerns that DART will hurt its bond rating by deploying its cash on both projects at once.

Thomas told the board last week that debt tied to the Cotton Belt won't hurt the agency in the bond market.

Timeline for federal funding

In the different scenarios, DART is angling for a federal grant of between $325 million and $650 million for the downtown rail line.

DART submitted a grant application for that project last fall, after the Dallas City Council approved a Jackson Street route that was half street-level and half tunnel. But the agency later told Dallas that such a path was not feasible, and now many business leaders and city officials are pushing for the rail to be constructed underground.

That setup would double the rail's cost and the amount of subsidies that DART would request if the agency also pursues the Cotton Belt.

If DART includes a subway version of D2 in its long-term financial plan, then the agency will immediately ask the Federal Transit Administration for an 18-month extension on its D2 application. Local officials expect they would get a response on the extension by the end of the year.

Assuming that an extension is granted, DART and Dallas city officials might work out a new route for the subway by next spring. The transit agency would submit a revised application to federal authorities by September 2018, said Steve Salin, vice president for rail planning.

FTA reviews applicants' financial plans and rates projects based on factors such as congestion relief and cost effectiveness. Projects must score at least a "medium" rating to advance through the process and be considered for funding.

If DART's revised application for D2 is filed by 2018, then the agency would get a rating by February 2019. DART officials are confident that a "medium-high" rating would position them to get the funding they want, though the sum would be negotiated later, Salin said.

If the agency decides to pursue the full Cotton Belt and the downtown subway but doesn't get $650 million in subsidies for D2, the subway would be deferred, agency officials said.