Minecraft – Can Pigmen build nether portals

Since version 1.5, this hasn't been much of an issue, as that release introduced a rule in the mobs' AI to avoid rails unless they are chasing after the player. Although I have still found Zombie Pigmen appearing on the tracks, this is now not as much of an issue as it was in previous versions.

Zombie Pigmen are able to spawn on rail tracks, so removing the walking path on the side will do nothing. But as has been mentioned, adding blocks above your tracks will prevent them from spawning and help keep them from walking onto your tracks 100% of the time. This is a common "fix", and has been around for quite a while, and it doesn't seem like the developers have any plans to stop this fix from being possible.

The following blocks can safely be placed above the tracks, and will not suffocate you:

• Glass panes (I would really recommend this one, since they are "cheaper" than glass blocks, works with stained glass panes as well)
• Glass blocks (works with stained glass as well)
• Glowstone blocks
• Leaf blocks
• Iron bars
• Fences (of all materials)
• Half-slabs (of all materials, note that they must be single, NOT double slabs)
• Stairs (of all materials)
• Trap doors
• Pistons (both extended and retracted)

There are other blocks that would work, such as Beds, Chests, TNT, or Enchantment Tables, but I have excluded them from the list due to being impractical.

This is most likely a rounding bug where the spawned portal in the nether, when trying to find a portal back in the over world, does the search but due to rounding and the 8 to 1 conversion rate, it will not find your original portal.

If you want a fix to this its the portal in the nether you want to destroy so that you can have it randomly generate a new one and give it a go. The problem is this means you have to hop to the nether, destroy the portal, store your gear and then die. When you go back into the nether your portal is going to be a bit of a ways away so make sure that wherever you store your gear it is -very- obvious to find it again.. Make sure you write down your coordinates and the like.

If hopping back into the portal to the over-world did not bring you to your original portal, it never will.

Please note that this rounding is potentially how to fast travel via nether hopping (hop into one portal and back out again to move 'forward' in the over-world).

Hope this helped.