Saving "Read Only" tracks

[szln6z]

I have the MRL layout from TrainzProRoutes. I added trackmarks and went to save, and it said I could not because it was read-only. So, I changed the name of the route to "MRL Rev 2" and was able to save. Then I added a few more trackmarks and went to save "MRL Rev 2" and I got the same read-only message so I had to save as "MRL Rev 3".

Question: how do I change "MRL Rev 2" so it is not read-only and I can save it without having to always rename?

Thanks,

James