The transit authority staff is returning to the Metro board this week to discuss its plan to divert some Blue Line trains at rush hour, a plan the staff says it can implement in June 2012. The discussion is on the agenda for the 9 a.m. Thursday meeting of the board's Customer Service and Operations Committee at Metro headquarters.

The shift, sending some Blue Line trains over the Potomac River on what is now the Yellow Line bridge instead of through the Rosslyn tunnel, will affect the travel habits of thousands of riders. The staff recognizes the need to prepare riders who might take advantage of the new service, or who might wind up on the wrong train.

To envision the scope of the communications challenge ahead for Metro, think about every place you see a Metro system map. They all have to change to reflect the reroutings that would send a third of the peak period Blue Line trains from Franconia-Springfield over the Yellow Line bridge and onto the Green Line up to Greenbelt. Meanwhile, the transit authority would add three trains per peak hour to the Orange Line, operating from West Falls Church to Largo Town Center, the current terminus for all Blue Line trains.

And it's not just the 5,000 rail system maps that will need to be reprinted and reinstalled in stations and on rail cars. Metro also would have to change 2,600 station signs and pylons. More than 1,200 fare charts for fare vending machines and station kiosks also would have to be altered.

Train operators and station managers would need to be trained for their roles in explaining the changes to riders.

In its report to the board Thursday, the transit staff promises to develop "a communications plan that not only clearly describes the expansion and resulting changes, but also involves customers, stakeholders and employees in the change to ensure public support and quality service."

The staff and the board have been discussing the proposed split for several years. Last summer, I invited readers of our Commuter page to suggest ways of designating the services that would minimize confusion. Should the new services get new colors, or should they adhere to the current color scheme while changing the destination signs?

The new report to the board focuses on how best to communicate the changes to riders. How do you listen to Metro's messages and what's most likely to get your attention?

The report suggests that riders will be most attentive to messages about the service change that focus on what's in it for them, describe the changes clearly and in detail and contain practical information that rides can act on.

A rider reading those conclusions might ask whether Metro had to pay for the information about what transit users need. But given Metro's past problems with communication, I find it encouraging that the staff is making the riders the central focus for a carefully developed information plan.

Compare this approach with the December announcement about the bag inspections, which amounted to: We've decided to stop riders at random to see if they're terrorists. Watch for a brochure.

No, this new approach to the riding experience promises to be different. But since it's been a while since we discussed the planned split, let's briefly review the three service problems the Metro staff wants to do address with this solution:

* Metro and its riders are aware that there's a problem keeping Orange and Blue Line trains close to schedule as they squeeze through the Rosslyn tunnel.

* Connecting what will eventually be the new rail line to Dulles will add trains to the congestion at Rosslyn.

* The destinations for many Virginia riders are now on the eastern side of downtown Washington.

Metro says that while some Blue Line riders heading for Rosslyn, Foggy Bottom or Farragut West would be inconvenienced by the diversion of some rush-hour trains, the realigned service would help the rail system match the new ridership demands while clearing room in the Rosslyn tunnel.

The Thursday presentation is for the information of the board members and the public. The board has not voted on the Blue Line split.