About the Railgun, from the article @ChrisPAR shared, it seems like the ability to create a new Railgun instance was shut down as of June 1st of this year and that all Railgun instances will stop functioning on January 31st of next year (2024).
As for the Optimized Partner Program, I cannot find any information about it. On their website, they advertise the One Partner Program and the Self-Serve Partner Program, but it seems like iFastNet would not be registered with either of those (from my perspective). Cloudflare no longer has a list of companies who are enrolled in a Partner Program, and the last article I can find about the Optimized Hosting Partner Program is from January 6th, 2014 (1&1 Internet).
From what it seems like (to me) is that Cloudflare is suggesting that clients use their Cloudflare Tunnels / Argo Tunnels in place of Railgun in most instances.
P.S. Sorry that this is a bit off-topic 