True, most of the Beta Train will forever remain a mystery. But I was surprised that I could come up with an entire section on it, and even more surprised that 99% of it involves the last car, where you kill Ourumov to save Natalya.

In this Beta shot, we can see that the level is pretty much the same as it is now. The only difference is the glass with the circles and lines in front of the computer. It's obviously not there now (right), but you can definitely tell that it's missing, with the empty window frame. I'm surprised that no one noticed this.

Here are two more screenshots, where the glass target is slightly visible. It really makes you wonder... Why? We don't miss this thing at all. It serves no purpose. But why would Rare even bother to take it out, and leave an empty 'window frame'?

The rooms at the back of train: I agree that Trevelyan and Xenia need a place to be, so it can really look like they escaped. But with a Gameshark, you can go through the door that slams down, and open a wooden door to another room, where you'll find a door that display's the message "THIS DOOR IS LOCKED". That's a little bit too much detail if you ask me.

Rare sure went to extreme lengths for detail! Two rooms, one of which you should never be able to get to, would never be needed just for detail. It's my theory that you once had the whole last part of the Train to yourself (and Natalya) after Trevelyan and Xenia left. This would make it a bit harder for first timers to find the trapdoor in the floor, so the space needed to be smaller. Got a better idea?

Okay then, I hear you wanting to know what's behind to door. Well, you can actually open it! With a Gameshark, you can unlock the door to see... nothing, just the sky. Meaning that if there ever was a hidden room, it's gone now. I don't think that there was a hidden room though, just the door to "show" you that you can't escape through there. But why would it be openable??? Why wouldn't it just be "painted" onto the wall? Probably just easier to program it that way.

Another thing people want to know, is the reason behind the Train's length. You get out to escape, but you have to run quite a ways, past several cars to escape. There's also an open roof hatch, but we can't see inside. But of course Gameshark once again allows us to see more. With the Moonjump code, you can jump up and see the train from a bird's eye view. You can see the sides of the train, but instead of a train car underneath the open roof, it's just empty space where you can see the tracks. Just there for completion.

The Chopper noise. Everyone has heard the sound of the chopper taking off after saving Natalya. It's there to inform you how Trevelyan and Xenia are escaping. I really doubt that there ever was a chopper in that level. Just another thing for completion, along with the opened roof hatch to make it look like they really did escape with a chopper that had been on board the train. But that doesn't mean that the graphics for a chopper in this level weren't created...

I read about this somewhere else. At the start of the train, there are boxes and crates. But when you enter the Train from the Depot (right), there are no boxes (screenshot made with no endings code to see inside Train from Depot). It's just a minor thing, and I think the programmers just left out the boxes from the Depot because they aren't needed, and thought no one would notice.

Lots of people want to know where the door near the start of the train goes. Well, it doesn't go anywhere. It's another thing that's just there for completion. Even if it did open, we see from the Depot shot (right) that it's just a door to exit, and it doesn't go anywhere.

Another strange thing about the Train is the accommodations it has. It has quite a few toilets in it, almost more than the number of guards! There are also couches, and a bed, as well as cushy cars with seats. All of this was likely just added for decoration and detail, to make it look like a real train. It looks more like a passenger train than a missile train... 

Walk Through Doors, to make it easier to get to the room at the end of the Train: 800364CB 0000

Unlock the Train's last door: 801CC4DB 0000

801E8D37 0028, 801E8D39 001D

Walk Through Doors, to make it easier to get to the room at the end of the Train: 80031A1B 0000

Unlock the Train's last door: 801B386B 0000