It doesn't take much hindsight to know that the Royal Shakespeare Company's epic 1980 adaptation of "Nicholas Nickleby" created an influential theatrical mode.

	Joel Ripka as Pip, left, and Jeremy Gender as Herbert in "Great Expectations." Click photo for larger image. "Great Expectations" Where: 937 Liberty Ave., Downtown. When: Fri.-Sat. 8 p.m.; Sun. 2:30 p.m. Through March 19. Tickets: $8-$15. 412-394-3353.

The key is an acting ensemble that narrates its own story. Individuals or groups slip in and out of narrative voice to describe characters or scenes, often the very characters or scenes that they enact. In this manner, a dozen or so actors can play a great many more characters and epitomize, with energetic pace, a very large story.

At its best, the "Nickleby" mode provides a rush of energy that sweeps the audience along in pure narrative pleasure. It is also easy to parody, given to Monty Python-like narrative leaps such as "affairs went from bad to worse," "she rapidly became the belle of London" and, "and so two years passed." In other words, narrative economy requires that the "Nickleby" mode break the theatrical commandment to show rather than tell.

This mode lends itself well to another great sprawling Dickens novel, "Great Expectations," adapted by Barbara Field and directed now by Rich Keitel for Prime Stage, Pittsburgh's theater for families.

Keitel is an enthusiastic proponent of the "Nickleby" mode, and the result is a 13-person ensemble that can be greater than the sum of its parts. That is, although individual actors vary in ability, the ensemble pulls them along. The occasional narrative cliche is a small price to pay, and as always, Prime Stage has a subsidiary goal of sending audiences thirsting for Dickens' unparalleled richness back to his original novel.

Like "Nickleby," "David Copperfield" and "Oliver Twist," "Great Expectations" dramatizes a tale of personal growth. For its hero, Pip, that growth is moral. Pip is the ordinary village orphan who mysteriously comes into the financial expectations of the title. Suddenly ensconced as a gentleman, he must learn to navigate the rapids of class, love, loyalty and betrayal.

Keitel is fortunate to have the capable Joel Ripka as his Pip -- and his own son, Daniel Keitel, a fifth-grader, to play Pip as the small boy who meets a mysterious recluse, Miss Havisham, and her fascinating ward, Estella, and then has a formative meeting with the fugitive Magwitch.

Pip meets the delightful Herbert Pocket, the secretive lawyer Jaggers, the eccentric Wemmicks and various other survivors of adaptive shrinkage. I do question Keitel's decision to have the actors act in the flowery accents of Dickens but recite narrative links in their own voices and accents. It calls undue attention to the artifice that sometimes invokes the comic compression of the Reduced Shakespeare Company.

Among the actors who reveal Dickensian eccentric flair are Jeremy Gender (Herbert), Chelsea Mervis (young Estella) and Gunther Kusior (Magwitch). Tim Winski has it as Wemmick but not as the pompous Pumblechook or hated Drummle. Kendra McLaughlin never finds the ghostly quality of Miss Havisham, even though Keitel underscores her with her own melancholy piano theme. Mark Tierno plays dumbfounded very well as Joe Gargary. Even those actors who lack polish have a clear caricature to project.

In the intimate space at 939 Liberty, seating about 75, "Great Expectations" comes in at just two hours. Because I was doing double duty Saturday, rushing to a late-night show, I had to miss the last 10 minutes.

Of course I already know the ending, not just from the novel but from the great 1946 David Lean movie. Sometimes a play can send you back to a beloved movie as well as a novel.