Powered rails do not always increase the speed of Minecarts. I've done some testing in creative and survival it seems to only happened in the nether. Sometimes the minecart will get up to slightly slower than walking speed and then not increase its speed anymore.
Comments 4
I did some more messing around with powered rails and it seems if you hold forward while crossing the powered rail it resolves the problem. However I don't think this is the intended functionality.
Cleaning up old tickets: This ticket has not been updated recently (~1 year+) so is being closed as Cannot Reproduce. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines.
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Thank you for your report! This issue affects java MC-51382. Please read up on it and @me in the comments about any differences and similarities between yours and MC-51382. Have a great day! 🙂