Vehicles of different route types behave differently with realtime data (MQTT vehicle positions)

I have observed on my own test Digitransit instance that buses are shown both on the linear trip timetable and on the actual map as markers, where trains are not shown on the route map even when they have position data, but they are shown on the timetable „progress”.


These feeds are configured identically: trip updates through OTP router config and high frequency real-time positioning with MQTT and the related configuration for subscribing in realtimeUtils.js. The data is getting to the browser, the websocket is working, as that is the data source for the linear view.

I'm not sure if that was a fluke or what, but upon zooming on the map with no route selected, the position of a train seemed to appear, with the route short text on it just briefly, and it was gone the second after.

Could someone please point me into the right direction as what configurations are to be done and where in order to make these function the same?

Start with realtimeUtils.js and the browser websocket data used by the linear timetable view. Reproduce the configured MQTT vehicle-position feeds for buses and trains, then compare how the map markers and timetable progress consume that data. Done means train positions behave consistently on the route map and timetable, or the required configuration difference is documented.