The Necropolis El is a tram that runs through the whole of the Necropolis, from Southern Necropolis all the way to the Necropolis' Heart. It has a great many tiles in its path that serve only as its tracks, snaking in lines between the zones that it covers.
The El was a pre-collapse invention, a superfast tram made to cover large distances quickly. A couple hundred years past its prime, the El now lives primarily to bring terror to the hearts of all those that behold its terrible form: the tram will gib any player or mob caught in its path when it arrives. Players with Silicone Skin stay intact and resist this gib, but they will not survive the impact itself. The El makes a loud rumbling noise as it approaches that steadily increases volume, giving you 5-6 seconds to run away and beg your corpmates for a new pair of trousers. The El's instant deathray seems to happen just as it transitions tiles, before it actually reaches the tile where its prey is located, so don't wait around!
Using the Tram
The tram occasionally does useful things, like gib Zardoz and other necropolis mobs. Players can also ride the tram for free! All that's required is to enter the tram when it stops. Make sure you're standing on the platform for the tram, not the track tile where it arrives, or you'll get squished. The El has five stops: one in Southern Necropolis, one in Necropolis Gate, two in the Necropolis Floodplains and one in Necropolis' Heart. This is the best way to get from one part of the Necropolis to the other if you can't fly a plane, fly your body or blink. Unfortunately, the El is still pretty slow, since you have to spend time waiting around for it to show up, so flying or blinking around is still better.
The only other alternative is to run the El tracks on foot. This is technically possible, but because of the train's great speed and the stranglevines that inhabit the tracks themselves, the life of expectancy of anyone attempting to do so is very, very short. Players with Leapfrog can outrun the train, but this is still very dangerous, and the tracks don't hold much to see outside of the parts that have dedicated platforms and landing pads.
It is believed by several fringe groups, cults and conspiracy theorists that the Necropolis El is really Mr. Bone's Wild Ride manifesting itself in one of its myriad forms, through the dark dreams and nightmares of Necanthrope. If this needed any confirmation, there is a skull throne inside the train, to rattle spookily as you trundle along!