The practice of using the same transit vehicle and/or operator to serve more than one route without returning to the garage. This method is often implemented at common terminals or where two or more routes share a common endpoint or are in close proximity. Interlining can improve operating efficiency and enhance passenger transfers. By minimizing vehicle requirements and reducing the need for transfers, interlining can enhance overall service performance. It is also referred to as through routes, interlock routes, or interlocking.