If it's part of the track, the lighting is almost definitely pre-baked into the textures as a seperate lightmap. Theres no reason for them to be calculating that in real time.
Also, note that the steps on the metal ledge thing lead up to a flat platform with no opening.
I see no reason why this couldn't be from the engine. Theres really nothing amazing about it. They nailed the lighting, but that doesn't really mean that they did that using the engine. They most likely did the geometry, set up a realistic light source, and ran it through some complex program over the course of several hours in order to generate a lightmap, which they then applied to the geometry to give it the realistic lighting you see here. This is a technique that's been used since quake 1. Probably before then. They just perfected it here.
Unified lighting models are not always the best way to do lighting, sometimes simpler is better.