The opening localization for railway oil tank wagon using machine vision technology is an effective way to load petroleum automatically. In this paper, we introduce a localization system for the opening of railway oil tank wagon, which consists of industrial camera, lens, LED lighter, industrial PC, and IO module. In addition, we also propose a shape matching localization method, which can overcome the adverse effects produced by illumination changes, various types of railway oil tank wagon, and various poses of camera. The shape template is extracted from a standard opening image using edge detection and shape fitting methods, which can help avoid the randomness of template selection. An optimized similarity measure is exploited to avoid the edge extraction, so that the threshold setting of edge extraction can be avoided. In addition, we also exploit scalable template to find various types opening and exploit image pyramid during shape matching procedure to gain a speedup. The indoor and outdoor experiments show that the localization system and the proposed method fully meet the requirements of practical industrial applications.