The Metro Transit Authority rehired Bechtel, Inc., as its construction supervisor yesterday after Bechtel officials promised to pay increased attention to the quality of construction.

The Metro board had deferred acting on the $19 million Bechtel contract a week earlier as members expressed dissatisfaction with the quality of Bechtel supervision. Board members cited the accident that caused the flooding and closing of sections of the subway's Blue Line and poor concrete work at the Cheverly Station.

In a letter to Roy T. Dodge, Metro's assistant general manager for design and construction, Bechtel vice president J. G. Dillon outlined a seven-point program that would put managers and inspectors closer to the work. Among other things, Dillon wrote, "We will increase emphasis on construction quality problems and risk to schedule."

In other action yesterday, the board instructed the Metro staff to come up with a proposal on how to handle the cutback of Metrobus service to Fairfax City.

The Fairfax City Council voted Tuesday night to replace all-day Metrobus service with rush-hour-only charter service. Metro will have to decide quickly how to realign its routes and then present the proposal at a public hearing.

The new charter service is scheduled Jan. 2, and Metro does not want to be running busses Jan. 3 because of some procedural error.