1. A method of implementing a computer based interlocking system for protecting trains traversing a guideway system, said guideway system comprising guideways comprised of guideway objects which influence movement of trains in the guideway system, comprising: providing a data base of prestored rule sets for a plurality of guideway objects, said guideway objects defined by entry and exit points, the entry point to at least one guideway object being a virtual gate, the rule sets defining conditions for a respective guideway object which must be met before entry through a virtual gate of said object is permitted; inputting a high-level description of a guideway system layout including all of the guideway objects that make up guideways in the guideway system; processing by a computer implemented interlocking engine the high-level description of the guideway system layout using the prestored rule sets to form an internal guideway data model; supplying status signals from guideway objects and control requests to said interlocking engine; processing said status signals and control requests by said interlocking engine in real time with reference to said prestored rule sets and said internal guideway data model; and outputting control signals denying control requests that would result in unsafe conditions.