So today I was torrenting GTA VC and decided to launch some GTA III to get myself back into the classic GTA mood. I had died and spawned at the hospital at the starting island, and saw the underground tunnel. I immediately went down there as my mind went straight to GTA IV's Ratman and of course Darkel. As soon as I went down there some "fog" (what I presume to be steam coming from pipes rather than fog) appeared what happened next was very strange.
I had started walking really far to the right of the tunnel, like a few real minutes, dodging the trains that appear about every 45 seconds. Then, things started to get weird because there was constant blue helling and texture pop-outs. Pic
I had noticed that this blue hell area was solid and continued to walk down for a few minutes. Pic
I was starting to wonder where these trains were coming from, then I found that they spawn from the Blue Hell area proper, and sometimes just pop in from existance in certain areas. Pic
After walking again for a few minutes, I finally came to the station in Shoreside Vale. However, as I was leaving the station I accidentally hit F and entered the train. The train started to move and I hit F again to exit, but the game bugged out and sent me on top of the train, and therefore on top of the underground itself. Pic
I continued to walk around until I reached Stanton Island. I found a large structure blocking the way, but fortunately it is passable. Pic
But, this is a downside. When you reach this area and Stanton Island the underground tunnel finally starts to get very buggy, it turns invisible and his hard to navigate. I tried to reach the sea however the tunnel finally turns non-solid and I clipepd through and fell into blue hell. Pic
Overall, with Ratman and Darkel sightings, strange omnipresent fog, phsyics defying trains, and of course a large glitch that lets us EXPLORE blue hell, this is a pretty interesting area and I will make sure to investigate it in the future.