T-45d power armor

An older, inferior model created as the result of the power armor research project, this type of armor has seen its first deployment against the Chinese invaders in Alaska, where it contributed tremendously to the American war effort. Nearly two centuries later, a hundred or so of these suits are used by the Capital Wasteland Brotherhood of Steel, of course, with modifications and makeshift repairs.

While it is similar to the pre-War T-51b Power Armor, it looks even more clunky, with riveted steel plates instead of the more rounded, streamlined looks of T-51b. Its under-armor suit, also known as Recon Armor, is also more complex than that of the T-51b's blue one (wires, metal elements).

Most of the time you will have to take badly damaged suits from corpses. However, by the time you acquire the training necessary to wear power armor, you should have had the opportunity to scavenge several badly damaged suits and combine them into a single suit in a decent state of repair.

Power Armor Training is required to wear any power armor. You can be trained by Paladin Gunny who resides in The Citadel's meeting room.

Trivia

 * According to the Fallout 3 artbook, the power armor was designed directly in 3D, skipping the concept art phase.
 * You can repair Brotherhood Power Armor with the T-51b Power Armor, but you can't do the reverse. It might be a bug or it might be the fact that the T-51b Power Armor is more advanced and uses more advanced parts.

Appearances
This armor is the most prevalent Power Armor model in Fallout 3. For some reason when wearing this suit you cannot use the large lamp attached to the helmet instead of your Pip-Boy light.