For the second time in a few weeks, Maryland transportation officials gathered engineering, financial and transit firms Monday to solicit ideas for ways the private sector can help the state build and pay for a new light-rail line.

But the topic this time wasn’t a proposed $2.15 billion Purple Line for the Washington suburbs, which was the focus of a similar meeting May 15. This time the spotlight fell on plans to build a $2.6 billion Red Line through Baltimore.

Washington area transit advocates are eyeing the Red Line proposal because it could end up competing against a Purple Line for limited construction money. The state is seeking highly competitive federal aid to fund half of both projects, which could end up pitting the two against each other at a national level. Even if the Federal Transit Administration were to award money to both, the state would then need to find money to cover its share or pick one to build first.

The state’s transit advocates have been practically giddy over the prospect of an estimated $4.4 billion in anticipated new state transportation revenue over the next six years as part of the recently passed sales tax on gasoline. But that money will be in high demand for transit and road projects across the state. Allowing two expensive transit projects to consume large chunks of new tax revenues would require the politically risky move of limiting projects in the rest of the state.

Maryland officials have gone to great lengths to resist the appearance of playing favorites between a Purple and Red lines. At the private industry forum Monday, Lt. Gov. Anthony G. Brown (D) told reporters, “It’s certainly my intent that we won’t choose” between the two.

Brown, who is running for governor, added, “Now, that decision may be made for us,” referring to the possibility that only one might clinch federal funding.

A 16-mile Purple Line would provide a direct east-west transit connection between Maryland’s ends of the Metrorail system, MARC commuter rail stations and Amtrak. State officials have said new development around light-rail stations also would revitalize older suburbs inside the Capital Beltway, such as in Riverdale and New Carrollton.

A 14-mile Red Line would connect suburban communities west and east of Baltimore to downtown and Inner Harbor. It also would serve major employers, such as the Social Security Administration and Johns Hopkins Bayview Medical Center, and the Canton and Fells Point areas.

A Red Line is about seven months ahead of a Purple Line in the quest for federal funding because the Obama administration expedited its environmental review, which was approved in February. State officials say they expect a Purple Line’s federally required environmental study to be approved in September.

Rep. Elijah E. Cummings (D-Md.) told the group of several hundred people at the Baltimore Convention Center on Monday that President Obama “made the Red Line a priority of his administration” when the Federal Transit Administration chose to fast-track its environmental study.

Brown said state officials are still considering whether to pursue a public-private partnership for either project.