Railway has three support engineers who work on tooling + myself if you count me. (I have been more focused on customer migrations and classical sales as of late.)
One thing that I think we left out of the blog post which would have been helpful context is in our support tool, we have a queue of emails, Discord threads, forum posts, tickets, and Slack threads. Depending on the customer plan, we have an SLO assigned to the conversation. Enterprise people get a response in 1 hour, Pro in 24, and Hobby is best effort (usually 2-3 days at worst).
If we hit any of those timelines, the support on-call (a rotating person who is on the operations/GTM side of the house we call logistics) will get a page on PagerDuty. If the page is missed, it escalates up. We do a on-call rotation for support namely to make sure that we build the empathy for our customers for everyone at Railway while also testing if we built good tools that people know how to use. It's one thing to build something for yourself, a whole other thing to build for others.