Intercity rail service between Tucson and Phoenix has long been a topic of discussion in the state.

The Arizona Department of Transportation has studied the idea for years, which resulted in a final report a few years back on the possibility of a commuter rail system connecting the state’s two largest cities. That was followed by a series of route alternatives showing where a future rail line might lie.

It’s an ambitious proposal and not low-cost, either.

Carlos Lopez, rail planning program manager at ADOT, said early estimates for the plan range from $4 billion to $10 billion.

Lopez plans to present a review of the plan at Advancing Women in Transportation’s Tucson Chapter informational session Thursday at the Tucson Convention Center.

Lopez said the idea of intercity and commuter rail between the two cities is still in the early stages, although the process has been ongoing for years.

At this point, ADOT has submitted preliminary draft environmental assessments to the Federal Railroad Administration and Federal Transportation Administration for approval. That draft report should be completed by the spring or summer.

The federal government is one of the possible funding sources of the rail project, so it would have final approval on the plan.

But state funding also would be needed, Lopez said, because federal grants would require a 50 percent match.

Other options to build and operate the rail line include a public-private agreement of some sort, Lopez said.

Future feasibility studies are planned that would estimate ridership figures and costs to operate the system.

While ADOT continues to work on the rail plan and will hold public hearings on the environmental assessment, the realization of passenger trains shuttling people from Tucson to Phoenix and parts in between is years off.

Lopez said even if the state had funding in hand today, it would take eight to 10 years to complete construction.

Information and tickets to the Thursday information session can be found here: www.brownpapertickets.com/event/1337528

Down the road

Traffic on Valencia Road will be shifted to the newly paved eastbound lanes on the south side of the roadway on Monday.

This change will allow the contractor to begin work on the westbound lanes on the north side of the street.

This configuration will be in effect until end of summer.

The speed limit through the construction zone is 25 mph.

The city of Tucson plans road improvements on Benson Highway from Irvington Road to Interstate 10 beginning Monday.

Work will take place from 7 a.m. to 6 p.m.

Beginning Thursday, crews will start milling and repaving Benson Highway. To lessen the impact on drivers, the milling and paving work will be done at night from 6 p.m. to 7 a.m., Sunday through Thursday.

The repaving work is scheduled to be complete by March 18.

This pavement improvement project is part of the $100 million, five-year street bond program

More information on the Road Recovery Program can be found at www.tucsonaz.gov/streetbonds or by calling 837-6686.

Contact reporter Patrick McNamara at 573-4241 or roadrunner@tucson.com. On Twitter @pm929 and Facebook www.facebook.com/StarRoadRunner.