I stopped at the station in front of the viaduct under inspection. I made some random changes with lighting switches. Then the game displayed a message: signal passed at danger. I've reloaded the last checkpoint. After that, mission objectives disappeared.
Yeah, sometimes reloading the last checkpoint or a save will do this. I'm not sure exactly what causes it, but it's happened to me before on other routes as well. I'm afraid you're just gonna have to start over.
