The bug
Powered, activator and detector rails disappear when pushed or pulled onto a block they cannot be placed on, like soul sand, leaf, air or water.
How to reproduce:
Power the piston in the attached image, the soul sand can be by any block whose rails cannot stand on
❌ The rail will disappear instead of dropping.
Linked issues
is duplicated by 18
MC-155969
Powered, Detector, and Activator Rails pushed onto air disappear without dropping
Resolved
MC-157045
Powered Rail pushed into fences gets removed
Resolved
MC-161148
Powered, activator and detector rails are deleted when being pushed onto farmland
Resolved
MC-161636
Rails break without dropping item when pushed
Resolved
MC-163890
Pushing rails onto honey blocks with pistons makes the rail vanish
Resolved
13 more links
relates to 2
testing discovered 1
Attachments
Comments 7
It's not only related to soul sand. Actually the bug occurs when placed on any block you can't place rails on. ✔ Updated ticket
The rails will also disappear if moved into an "unsupported" state. Moving an inclined rail to a position without the higher block also causes the rail to disappear. Yet moving the higher block away from the rail causes the rail to pop off as would be expected.
Felix Jones
Why was this marked as a duplicate of: https://bugs.mojang.com/browse/MC-146928
The rail is actually deleted...as in disappears. It doesn't pop off, it just ceases to exist.