Disaster maven Byrne--who's previously wreaked havoc in Skyscraper (1984), The Dam (1981), and The Tunnel (1977)--now hitches up with a nerve-gas-leaking, runaway train for a ride that only gradually works up to full steam. Byrne starts in first gear with a man racing to prevent an unspecified disaster, but soon throttles down. After Draegler Chemical Corp. engineer Gil Ellis fatally crashes while trying to elude company goons, the action slides into extended flashback detailing the past two weeks: In San Francisco, Ellis' ex-wife Karen starts life anew by taking up with dashing railroad exec Jim Eagen; meanwhile, at Draegler's Nevada desert headquarters, Ellis learns that the company's new product, Mannequin, isn't a pesticide at all, but a deadly, paralyzing nerve gas about to be railroaded west for use by Iraq against Iran. What's worse, Iranian terrorists plan to unleash the gas against American towns by exploding the shipment en route. Before Ellis dies trying to blow the whistle, he leaves a cry for help on Karen's phone machine. Off to Nevada runs the freshly minted widow, joining forces with Ellis' gun-toting new girlfriend, Sara, to combat venal Draegler execs and the terrorists. The women suffer torrents of blood and violent sex, but to little avail: the train departs anyway, soon leaking enough gas to paralyze the conductor and the Draegler honchos aboard. Will the terrorists succeed in gassing half of the West? Will Karen and Jim Eagen (Sara is felled by Iranian bullets) prevent the now hurtling, out-of-control train from slamming into S.F.? You'll flip pages to find out. Lacking the techno-detail that former engineer Byrne usually stuffs in, and inhabited by characters that evaporate on the page. But that final train trip's a zinger, quick and slick. In all, then, akin to an hour's wait on line rewarded by one heck of a roller-coaster ride.