Rules, standards, and instructions for installation, inspection, maintenance, and repair of automatic block signal systems, interlocking, traffic control systems, automatic train stop, train control, and cab signal systems, and other similar appliances, methods, and systems. Effective march 31, 19^6. [Ed.by] Interstate commerce commission, Bureau of railroad safety and service. [Washington], (U.S.gvmt.prtg.off. 1966) (Ex parte no. 171^^^