they disappear after 30 secs or so, theyre just used to track players movement
I think its in "config\railcraft\blocks.CFG"
I think its in "config\railcraft\blocks.CFG" and now called "residual.heat"
This and this
B:hidden=true
It might have happend if you updated from a older version and didn't delet the configStrange I'm on 9.2.2.0 and I see both, something's afoot.