Rust

Victorian railings marked the entrance, rusty and forgotten, coated in a green outdoor paint. A cold staircase with an ornate cast iron banister running down the center, lead to the swallowing chasm beneath. A cold, dark platform, damp from the winter morning dew, lay in wait at the foot of the staircase. Pots of tea and coffee, placed on the counter of a platform coffee shop, steamed merrily in the cool air. A wooden bench stood against a wall facing the tracks, screwed firmly to the chewing gum strewn floor, with a memorial plaque attached in the center.
With some kind of woollen scarf at his neck, a slender figure in a suit of black and dark grey and long coat, sat with an attaché briefcase upon his lap. A steaming throwaway teacup was at his side. His facial features, hidden by the shadow of the nearby pillar, seemed wise and well aged. His shoes were of the darkest black, laced tightly and polished perfectly. In the half-light, seeing where his legs ended and his feet began was a difficult feat.
A cold, to chill the bone marrow, the taste of rushing wind, erupting from either side of the slithering snake-like tunnel meant the arrival of a train. Encasing people like mice in a cage, a claustrophobic, two coloured cylinder of aluminium and ice cold steel would rush along the tracks and come to a halt with the whine of electrical motors. Metallic wheels and grills were underneath the carriage, like a giant heart in the belly of a cold-blooded snake, working its way through the undergrowth in a beautiful glissade. Fangs and hisses, below the surface, venom waits to disembarc.
Like a sentinel, a young woman stood a small distance from the track. Brown, high heeled boots ran up her leg, to the knee. Her coat fell just above, masking her skirt from sight. Her coat was of the finest cashmere mixed with wool. It had buttons, oddly out of place on her chest, like the tailor was drunk at the time. Her collar was slightly open, just to shield her from the icy wind, revealing the chain of a small silver pendant laying against her breast. Hair, dark brown, brushed her face and neck in the chilling breeze like a leaf kissing the surface of the ground before being lifted up once more.
The white and blue varnished brick gave the walls a metallic and surgical appearance, like the scalpels and clamps under operating theatre lighting would glisten. The brick ran the entire length of the platform. Opposite the platform, a cement wall, reinforced with steel rods, glowered at the onlooker, a great mythical being shaking its head and crouching warily. The opening to the endless, spiralling network of tunnels seemed to draw the eye like some indecent image that had been discovered by an unsuspecting guest.
A small walkway lead to a car-park, abandoned and assimilated by deviant teenagers. Cider with their underage sex and ciggerettes with their hoddies, striving to look expensive while remaining "street”. All their primal desires, seemingly satisfied by the bad company that meeting in a car-park could bring. All too suddenly, the night is over and commuters will have to walk disgustedly passed discarded condoms and plastic bottles: little reminders that corruption is strife among the corruptible.

What grade etc would i get for this description, have you anny suggestions? thanks

It is a very good observation of city life. Perhaps just a few too many words, to hold the readers attention, but, yes, I think you have a talent for story telling.
Good luck