From Liquipedia Starcraft 2 Wiki
Scrap Station is one of the maps released with the StarCraft II beta. Previously it served as the battleground of the third Blizzard Battlereport between David Kim (P) and Yean-Ho Lee (Z) (then still named: Scrapyard). The map was removed from the Blizzard ladder at the end of Season Two.
The layout resembles the Brood War map Paranoid Android. One of its main features is how as you expand as the game phases: you are moving closer and closer to your opponent.
 Official Map Description
Guard your half of the station from enemy attack. Rocks protect the main path to the enemy, more distant paths are open. The enemy is close by air.
 Notable Features
- Closer path available after rocks are destroyed.
- Smoke patches near shorter path and by Watch Tower.
- Island expansion between the two main bases.
- Two expansions blocked by debris.
- A single High-Yield expansion at 7 O'Clock position.
- Long walking/scouting pathing distance between mains
- Second longest walking distance of all the sc2 beta maps (about 45 seconds). However, if the rock paths are broken, the distance is about 20 seconds.
- Stalkers used to be able to Blink from the island expansion to the 1 o'clock main.
 Earlier Versions
In beta patch 9, there were made some changes to scrap yard to make the natural expansion easier to defend.
 Terran wall-ins
 Protoss Wall-ins
There are essentially two ways to wall of on scrap station. One is to have a pylon further back and to build 3 3x3 buildings at the ramp to give a sturdier wall. The drawback of this is that you have to reveal an additional structure. Otherwise, you can use a pylon in the wall off. This makes it slightly faster, and reveals less tech, but can be more vulnerable.
Patch 1.3.3 reduced the pylon power radius by 1, so make sure your wall-ins still work.