Use the "Exit Steam Workshop Beta" button on a game that has a working Workshop. Not easy if all of your games has the same problem. For me I was able to disable it on SimRail, then the workshop for TSC started working again.
Got the same problem, tried to get Nessland Lough route earlier today, but had to do with Hedborough North (legacy) instead! Trying to find a certain route in game would take a while, but might have an impact as a result of an outage. I guess it's now a waiting game untill further notice for all!
If you have another Steam game that uses WS, open it and click on the Exit Steam Workshop Beta, then open TSC WS.
If anyone is interested I use this page for scenarios from the workshop, it is made by WarwickRail, it is way easier for searching if your looking for scenarios for a specific route https://www.railsims.com/TS/ts-menu.php
