So i'm at the mission "The Molecular Level", and i asked the Railroad to help me build the signal interceptor. It said i needed to talk to Tinker Tom, but i got a usual response to barter. Then, I noticed the signal interceptor plans in his misc. inventory. I took them, and now the quest set me back saying to talk to either the railroad, minutemen, or the brotherhood. I can't give the plans back because it doesn't show up in my inventory when I try to give them back. And if I try to talk to the minutemen, the railroad again, or the brotherhood, it doesn't say if i need help building the plans. I need help fixing this, and progress through the story like normal.

See if you can build the first part. My guess is that Tinker Tom will show up after it's done and you can continue.