This paper provides a simplified solution to the general asynchronous track fusion problem of the authors. The original solution solves a practical sensor to sensor track fusion problem when the sensors used are asynchronous, communication delays exist between sensor platforms and track fusion center, and tracks may arrive out-of-sequence. The new fusion rule is derived under mild assumptions. The rule does not require the synchronization of tracks for the purpose of track fusion. The Bar-Shalom-Campo fusion rule is derived as a special case of the new rule for the case of synchronous tracks. This rule is also illustrated on an alpha-beta filter.