Requested Information:

“I have been consuming the Metlink GTFS-RT API/data feed and have a few questions that I hope someone can answer:

1. Is there a way to check if new position data is available without pulling all position data again? The Last-Modified/If-Modified-Since and etag headers don't appear to be supported.

2.Are there any soft or hard api limits? I would like to experiment with timely data but do not want to poll too frequently especially if it is not possible to avoid pulling stale data repeatedly.

3. How do rail positions work? Rail sources frequently report precisely the same lat/lon across different timestamps - and update much less frequently than buses.

 4. Sometimes a vehicle lat/lon is reported as 0,0. Does this have a special meaning or should it just be ignored?

It would be great to hear answers to these questions and any other guidance/recommendations on using the GTFS RT data.”