Minecraft – What good are all the golden swords looted from zombie pigmen

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.

I'm not really a Minecraft player, but a quick glance at the wiki indicates that you should (like with other metals) first smelt raw gold ore in to Gold Ingots, using a furnace.

These ingots can then be used to craft weapons and armour (which you don't want), but also used to create Clocks and Powered Rail.

You can also combine 9 ingots in to a Gold Block, these can then be used for construction (if you want a nice golden house or something) or these ingots can then be used to craft a Golden Apple, which instantly restores your health.

Given the supposed rare nature of Gold within the game and the items you can create with it, I would presume Gold's most important usage is in the creation of Powered Rail, which (from what I see here) vastly increases your construction options with mine carts.