Darwin Evolved

[WantStuff]

Has anyone identified how to download the "Darwin Real Time Train Information snapshots" files available on the Rail Data Market?

The RDM page has very little usage information. It does have a "Try-it" page that generates the POST request with a "x-apikey: <consumer key>" header, but it responds with HTTP 401 and a has blank response body.

If I remove the the x-apikey header I receive "Failed to resolve API Key variable request.header.x-apikey"

This appears to show that the gateway is receives the x-apikey header but rejects the key/entitlement.

So either the provided consumer key is not authorised for the snapshots product, or I am missing something, or the RDM snapshot feature is not actually live.

[jezinwo...@gmail.com]

Some guidance that we have just posted is here.

Hope it is helpful, but feedback appreciated.

Jez

On 3 Jul 2026, at 13:49, WantStuff <wants...@gmail.com> wrote:

Has anyone identified how to download the "Darwin Real Time Train Information snapshots" files available on the Rail Data Market?

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[WantStuff]

Hi Jez,

Thanks for the instructions. I have now managed to get the Darwin snapshot download working, but I found two issues that are likely to affect other users.

The first issue is with the JSON request body shown in the instructions. I copied the example body directly from the instructions, updated the date and hour but when pasted into the RDM “Try it” page, this was reported as invalid JSON.

The problem turned out to be that the JSON example contained non-breaking spaces rather than normal spaces. When I manually retyped the same JSON body, it worked correctly.

I suggest that your example should be plain text or not contain any newlines or spaces, e.g. {"date":"2026-07-03","hour":"23"}

This is worth correcting in the instructions because users are very likely to copy and paste the example exactly as provided.

The second issue is with the first download URL I received. The API successfully returned a signed Google Storage URL, but opening that URL in a browser returned the following XML response:

<Error> <Code>NoSuchKey</Code> <Message>The specified key does not exist.</Message> <Details>No such object: prod-kafka-snapshot-bucket/20260703_23.xml.gz</Details> </Error>

I then submitted the same snapshot request again and received a new signed URL, which did work. This suggests the API can return a signed URL before the underlying snapshot object is actually available, or before it is visible in the storage bucket.

It would be useful if the API checked that the object exists before returning the signed URL, or returned a clear “snapshot not available yet” response instead. At the very least, the documentation should mention that callers may need to retry the request if the returned signed URL gives a NoSuchKey response.

Finally, could you also confirm: 

1. are date and hour values are expected to be UTC or UK local time, 

2. how long after the hour the snapshot should normally become available?

Regards,

Martin