Is it intentional that Greater Anglia trains are missing from arrival predictions ?
For example, 910GBRIMSDN seems to be the code for Brimsdown station, but the API returns a 200 status with no content:
http://ojp.nationalrail.co.uk/service/ldbboard/dep/BMD confirms that trains are stopping there today.
The same happens at Enfield Chase (Gt Northern) and at Hackney Downs only overground arrivals are reported.
It seems odd that the journey planner is able to route journeys through those lines, but the API is unable to back them up.
I’d also say that if the data for these lines is missing, the result ought to be an error code that identifies the reason, not a 200 response.