SIRI > SIRI to GTFS-realtime
A Java-based command-line utility to convert from the SIRI format to GTFS-realtime.
onebusaway-gtfs-realtime-from-siri-cli 
We provide a utility to convert real-time public transit data in the SIRI format into the GTFS-realtime format.
For more information on running the tool, check out the latest project documentation:
Other GTFS-realtime Resources
Be sure to check out all our GTFS-realtime resources.