Just Tell Me When We're Dead! / Eth Clif

From the back cover "When Jo-Beth and Mary Rose follow their runaway cousin Jeff to a deserted island and amusement park, they get more than they bargain for! After searching the empty playgronds and picnic areas for Jeff, the girls stop to rest in one of the small trains used for rides. Since no one's around , they never expect the train to suddenly jerk to life, whisking them through the dark Tunnel of Terror. .... Hank on till the surprising end!!"