Granted, for sheer, blow-your-hair-back, end-over-end thrills, the City Museum is hard to beat. But there is one attraction here in Mound City that edges out Bob Cassilly's monument to dreck-cess for thrilling the kiddies: The venerable Zooline Railroad is a guaranteed warm fuzzy for every kid, from newborn to nonagenarian. You can skip Big Cat Country, bypass the Jungle of the Apes and dodge the sea lion feedings, but if you attempt to leave the Saint Louis Zoo without taking the nippers on the train, you deserve every head-splitting decibel of shriek and whine that will plague you on the drive home, you cheapskate. Pony up the four bucks, take the damn train, hoot like a freakin' owl when you go through the tunnels, and wave like a deranged beauty queen at every crossing on the twenty-minute mile-and-a-half loop. It's your duty as a parent. And you secretly love every minute of it, anyway.