Fixed bug involving pistons and powered rails. This fixes BUKKIT-517.

src/main/java/net/minecraft/server/BlockMinecartTrack.java

@@ -81,7 +81,7 @@ public class BlockMinecartTrack extends Block {
         if (!world.isStatic) {
             this.a(world, i, j, k, true);
             if (this.id == Block.GOLDEN_RAIL.id) {
-                this.doPhysics(world, i, j, k, this.id);
+                //this.doPhysics(world, i, j, k, this.id); // CraftBukkit - Fix dupe with pistons
             }
         }
     }