I'm a cycling merit badge counselor. I prefer to do longer rides on rail trails. With the recent growth of Marcellous Shale gas here in Western PA., there is a lot more presence of Railroad on some of the older rail trails. Parts of the trails now share new rails. Something a few years ago would have never been expected. Slideshow of the day.
My grandson and I did a train ride/bike ride on the Great Allegheny Passage from Cumberland to Frostburg MD last summer. It's a three hr. ride to get there from my home. The greatest part of the experience was the trip home. A 10 year old who never in three hrs. stopped asking questions about the train and bike ride. Just recently moved up to a Scout.
We did an overnight camp/bike ride on the Montour Trial last fall. I had (4) young men complete their 50 mile requirement. The event made it back on the calender again this year.
Read carefully the requirements for a Railroad merit badge. As I understand, it can be done with out touching a model train. Mike .