Michael Crichton's "The Great Train Robbery" was a slight, casually diverting novel that read like a movie outline. The film version, directed by Crichton and opening today at area theaters, is in turn likely to appeal to many people as just the ticket for an undemanding but polished evening of movie escapism.

Rather like "Heaven Can Wait" last summer, it appears classier than most of the competing new releases and encourages a contented mood, as opposed to some more exciting form of stimulation.

Sean Connery stars as an intrepid, inscrutable gentleman thief named Edward Pierce, the master-mind of this genteel caper, purportedly based on the first successful train robbery of the Victorian period. To complete the theft of gold bullion from a double-locked safe, Pierce must leave his first-class compartment by the window while lugging several lengths of stout rope, navigate the roofs of several cars, gain entrance to a locked storage car where the safe is kept and return before the trip from London to the Channel terminus of Folkestone is over.

In the open countryside Pierce's arduous progress is slowed not only by the speed of the train but also by a succession of low bridges that threaten to slice his head off. The perilous nature of this task is intensified by a moviegoer's awareness that Connery isn't being doubled. For one thing the camera setups are simply too close to permit the use of a stuntman. Connery's close calls look agonizingly genuine, particularly one moment on the return trip when he slips and appears in danger of sliding off the side of a roof.

While the movie boasts an undeniably exciting highlight, it lacks an undercurrent of excitement. The climactic theft requires that Connery and his principal confederates, Lesley-Anne Down as his actress mistress and Donald Sutherland as a pickpocket and locksmith, make duplicates of the four keys needed to unlock the precious safe. In 1855 neither dynamite nor combination locks existed. The gang engineers elaborate schemes to locate and then copy the keys, but these preliminary capers seem more laborious than clever. They fail to build up a suspenseful head of steam.

It's beginning to look as if Crichton's filmmaking carburetor is tuned a bit low. Perhaps his approach is too dry a nd cautious to produce an explosive, uninhibited mixture of thrills and humor. His expository style is so deliberate that the ideas behind the thefts must be exceedingly clever in order to pay off. Unfortunately, they never are.

The superficiality of Crichton's last thriller, "Coma," seemed excusable if you'd read the miserably written novel it was distilled from. On screen "Coma" even benefited from a psychological subtext, reinforced by Genevieve Bujold's starring performance -- an awareness of the widespread suspicion and helplessness people feel when forced to place their fate in the hands of doctors.

"The Great Train Robbery" is Crichton's own invention, and it's disappointing to see that it hasn't been improved in any fundamental respect during the transition from novel to movie. It remains a minimal crime story dressed up by attractive performers and period decor. Many of the locations, props and settings, for example, are wonderfully evocative, but they evoke a Victorian illusion that seems to overwhelm the flimsy, expendable plot.

The script is so tidily unrevealing about the motives and backgrounds of the crooks we're supposed to identify with that it comes as a relief when Sutherland's character launches into a funny tirade at one point. It's a rare moment when the characters talk long enough to make themselves sound interesting.

Crichton has testified that Hitchcock's "To Catch a Thief" was the favorite movie of his childhood. The second-story work must have left an indelible imprint, because the most effective sequences in both "Coma" and "The Great Train Robbery" depict characters scaling walls, creeping across rooftops, tiptoeing precariously along catwalks and ledges.

It's a pity that Crichton's attraction to the mystery-suspense genre looks so dispassionate. Unlike Hitchcock himself or Brian De Palma, the most accomplished new inheritor of the Hitchcock influence, Crichton doesn't seem to be obsessed by terrifying reflections that the medium of films serves to sublimate. He seems instead a victim of his adroitness and self-control.

In the spirit of Connery atop that fast-moving train, Crichton needs to take things in hand more boldly and even recklessly. The decorous, picturesque virtues of an escapist entertainment like "The Great Train Robbery" are easy to like but just as easy to forget.