title: How to retrieve all available routes between two nodes with Overpass API
body: <p>I'm building an app which is provide the Map view (OpenLayers) for particular city(e.g. "London") with metro stations markers. So, user can click on pair of markers and I have to evaluate the shortest route between them.</p>
  
  <p>As geodata source I decided to use <strong>Overpass API</strong> <em>(OSM read-only API)</em>. I'm new in OSM and Overpass API isn't cleared for me. So, I can't figure out how to fetch all available routes (railway, roads, etc) between two nodes with <strong>Overpass QL</strong>.</p>
  
  <p>In summery, my goal is to fetch routes data, build graph representation from that and apply <strong>Dijkstra's algorithm</strong> in order to find shortest path. So, I stuck on the 1st step.</p>