AATI

golden steps

Like most people who live outside London, I find taking the Underground an exciting experience. There is so much to enjoy: the criss-cross tunnels (how did they design all that before 3D models?); the unfamiliar words (northbound); the felicitous match between line color and name (Northern black, Central red, Circle yellow); the excitement of being caught in a crowd hastening towards an escalator as if something amazing awaited at the bottom; the weird dirty cleanness of everything, grimy but smelling of disinfectant; the ghostly voice (mind….the gap); the prim voice (this is the Picadilly Line to…Cockfosters); the announcements to the effect that trains are running late, an absurdity when there’s one every two minutes and you don’t care which one you take; the disconnection between where you enter and where you exit, places that could be on different planets until one day you take a bus and confirm they are joined up.

But for someone like me who typically looks down when walking and climbing stairs, the Underground is also home to an artefact both humble and mysteriously grand: the nosing. Many if not most stairs have one, a metal strip on the front edge intended to provide grip as you step up or down. In places with moderate traffic like offices this would be rubber. In the Underground, rubber would be reduced to dust in a few weeks, and something more eternal is needed. The metal strips are a small inlay of pure luxury in the otherwise drab stairway. The metal itself is the color of rose gold. Rose gold is a recent addition to the range of metallic colors. It is the Gianduja of metallics, beguiling in small doses and pretty filling soon after. No one admits to loving it, though I once bought a laptop in that shade and am only slightly ashamed. The rose gold in the underground steps is resplendent, but mysteriously dotted with black grains like broken nuts in chocolate. In the middle of the nosing, a baffling inscription: AATI, followed by a phone number, like a graffiti on a toilet wall.

AATI, on further enquiry, turns out to be the acronym of Antislip Antiwear Treads International, a company that has a virtual monopoly in stair jewelry. I was wondering what the beautiful metal was, and it turns out to be Nickel Bronze. The black grains are Silicon Carbide. The idea is that the hard carbide beads embedded in the metal will wear down very slowly, and that the strip will only need to be replaced after decades. I was so taken by the look of it that I wondered whether one could use it to make rings and bracelets, merch for Underground aficionados. The answer is no: nickel bronze is a powerful sensitizer and will cause dermatitis on contact with skin. Silicon carbide is a defective crystal, the cheap black version of beautiful Moissanite. So the nosings are in essence humble costume jewelry, and we tread on it to make sure it knows its place. As I trudge up the stairs, I wonder whether one day there will be a revolt of the downtrodden, and AATI parures will be in the window at Aspreys.