The Interstate Commerce Commission's procedures for carrying out a congressionally-mandated dergulation of the rail industry were generally approved yesterday by the U.S. Court of Appels here.

The appellate panel, in a unanimous three-judge opinion written by U.S. Circuit Judge Harold H. Leventhal, said the ICC's regulations implementing the new regulatory scheme "are extitled to an extra dollop of judicial deference" and should therefore be allowed to stand for the most part.

Some railroad and electric utility compaines had challenged the new regualtory scheme as nullifying the congressional attempts at reforming the rail industry rate system, or as being based on inadequate information.

The new regulations were drawn up to implement the Railroad Reform Act of 1976, which deprived the ICC of regulating railroad rates except where it determined a railroad possessed "market dominance." The ICC was required to establish standards and procedures for making that determination.

Most of the procedures drawn up by the ICC resulted in guidelines weighted toward presumptions of market dominance and therefore allowing the ICC to set rates.

In reviewing those guidelines yesterday, the appellate court described them as the ICC's inital attempt at interpreting and implementing a new regulatory concept."

"It is important to keep in mind that the regulations are part of an ongoing process of agency scrutiny, correction and refinement," Leventhal said.

The Federal Trade Commission also entered the case, meanwhile, to argue that the ICC approach tended to "oversimplify a complex area." Leventhal disagreed, however, and said the FTC "ignored the potential contribution (to) . . . efficiency and manageability (to) . . . efficiency and manageability" that were involved in the ICC plans.

AS Leventhal pointed out, both the Justice Department and the FTC are more familiar with "coping with the fearsome complexities" of antitrust law and believed the ICC efforts were "marred by naivete."

The railroads, on the other hands, saw the ICC efforts as an attempt by the agency to "clutch on to its musty jurisdiction" over rail rates, Leventhal added.

"The commission identifies itself with prudent progress, moving into promising but unexplored territory, but hesitant lest vast areas of the rail carriage market revert to ruthless predators," Leventhal said.