I was looking as some links to the Workshop and I wondered how you find routes? Most of the fields you enter info are for the type of train or a route which brings up scenarios
I found this by clicking route, on a workshop route - seems to list all the routes on workshop https://steamcommunity.com/workshop/browse/?appid=24010&browsesort=toprated§ion=readytouseitems&requiredtags[]=route Although there is a tool out there too by Warwick Rail https://steamcommunity.com/sharedfiles/filedetails/?id=2361991441
The Workshop Routes Menu - Enhanced (second link provided by Danny above) is the only decent way around DTG's frustrating setup of their WS pages. And before anyone says "That's Steams fault not DTG!" Rubbish! other games (SCS's Euro Truck Simulator 2 for example) have easily searchable categories in their Steam WS pages go take a look.
That second link to the Warwick Rail page is very good and quite east to look thru. Although it is not perfect - a number of routes are shown as UK but are USA. I will bookmark that - Thanks Peter
Warwick Rail has to manually add new routes, but once he does, any scenarios for them are also added. He has to manually add new DLC, as well. Danny well beat me to it, and he is correct. That is how I found all 600 or so at the time.