> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-multi-modal-routing-network/os-mrn-overview/grade-separation.md). # Grade separation Where Transport Nodes have been split apart due to grade separation, the original node keeps the existing OSID and the additional nodes are indicated with the suffix --1 or --2, depending on the grade separation value. Also, the geometries of grade separated Transport Nodes are offset (5 cm in both the X and Y axes) to prevent routing software failure due to point spatial objects being at the same position. If a Transport Link has a different grade separation at the start and end node, the link is split. The OSID of the new Transport Node between the split links is indicated with a suffix of --S. One of the Transport Links keeps to original OSID and the other has the suffix of --S. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-multi-modal-routing-network/os-mrn-overview/grade-separation.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.