missing field "stations" when running fetch-lines

[hermanschaaf]

First off, thanks for this really useful repository.

When running ./target/release/tflgtfs fetch-lines --format gtfs on an Ubuntu 16.04 system, it mostly works fine, but there are some lines that return errors like the following:

Getting Timetable
	Line: West Midlands Trains
	Route Section: Birmingham New Street Rail Station - Shrewsbury Rail Station ...
Error decoding timetable: missing field "stations" at line 1 column 386

Upon investigation, it turns out this is due to a 500 error returned from the API, with the following contents (this is one example):

{"$type":"Tfl.Api.Presentation.Entities.ApiError, Tfl.Api.Presentation.Entities","timestampUtc":"2019-01-20T09:48:14.7140051Z","exceptionType":"ApiException","httpStatusCode":500,"httpStatus":"InternalServerError","relativeUri":"/line/london-overground/timetable/910GCHESHNT/to/910GLIVST","message":"No valid route found for 910GCHESHNT to 910GLIVST on line: london-overground"}

This is the case for most London Overground routes, as well as many other lines. Since it's a 500 error I will raise this with the TFL API folks as well, but just wondering whether the issue might be in the library? As far as I can tell it all looks fine and the request is correct.

[hermanschaaf]

I posted a question on the TFL forum as well: https://techforum.tfl.gov.uk/t/500-internalservererror-no-valid-route-found-for-x-to-y-on-line-z/844