Yes, I know, 50 minutes is not what the general public would consider brief. However, I recommend you consider the fact that I don't care. If you need help getting through Railway 4, this video should have EVERYTHING you need.
Intro: 0:00
Mechanics/Format: 1:04
Section 1: 8:24
Section 2: 21:07
Section 3: 31:46
Section 4: 41:15
Outro: 48:33