If you place a boat on a railway, and then push a minecart into it so the minecart is in the boat, you could travel on normal rails very fast, and without using powered rails.
To move forward you have to press the backwards key, in my case the default is the "s" key, and then you will move forward. to move backward press the opposite key, "w" and it will move backwards.
I demonstrate this glitch in a video i made on youtube:
https://www.youtube.com/watch?v=va-kK61FtZQ
Works on versions: Snapshot 19w40a,1.14.4,1.13.2,1.12.2,1.11.2,1.10.2
Thank you for your report!
We're actually already tracking this issue in MC-113871, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki