Next to the Tamar road bridge between Plymouth and Cornwall is the railway bridge, built by I.K. Brunel, and it has an unusual tube-like structure along the top. I used to think that the trains went inside this tube, and had to jump down onto the track at thend.
A childhood belief about trains

others believed things like this
- I used to believe that if the tyres were removed from a car, it would work perfectly on a railway track.— Anonymous Whistleblower
- Whenever I was upstairs on a bus, I didn't believe that it would fit under the bridge so I used to duck. — Dave, Lancashire
- if you eat toothpaste straight from the tube, you will get worms— wormelow
- I used to believe that George Washington died and turned into a bridge.— lara dean
- I used to want hemmoriods so I could use a "float tube" in the tub and have a cushy toilet seat like my dad.— Tami
- I used to believe that the lower level of the George Washington Bridge in NYC was named Martha Washington— Shayne