Review of fashion in 2012: All aboard the haute express

'The Louis Vuitton steam train stands as a leitmotif for the industry'

The catwalk at Marc Jacobs' autumn 2012 show for Louis Vuitton (PA)

Not one to hide his light, Marc Jacobs' autumn 2012 show for Louis Vuitton in March featured a full-sized, bespoke stream train, which models in Poiret-esque coats and cartoon cloche hats boarded, accompanied by porters weighed down with monogrammed luggage.

It stands as a leitmotif for the industry this year, the lavish departures and loaded decampments, nostalgic reveries despite relentless onward motion through changes of scenery, names and temperament. And that's before we even consider the whirligig of trends that the past 12 months have also thrown up.

Three new appointments, three new aesthetics – all of them at the very hautest levels of fashion, the very pinnacles of prestige – as Raf Simons, Hedi Slimane and Alexander Wang take the reins at Christian Dior, Yves Saint Laurent and Balenciaga respectively. The latter is a relatively new piece of information, announced last month; the former two have been picked over ever since John Galliano's exit first set the merry-go-round spinning in 2011.

Simons' final show in February after seven years at Jil Sander was one of those rare marvels: a collection that was as understated as its impact was obvious. The third in a triptych of couture-inspired, ineffable collections that had seemed to many an open pitch for the spot at Dior, there were mid- century bustier dresses made modern with sharp geometries; Fifties-era double-faced blanket coats, in camel, blush-pink and crimson made fitting going-away outfits. Its aesthetic coherence, a functional but formidable fragility, characterised the whole genteel mood of the season, and both audience and auteur shed tears during a heartfelt standing ovation.

In Paris the following month, Stefano Pilati's Saint Laurent swansong was touching – here was a designer who has for a decade managed the difficult task of fitting his own personality and that of his illustrious forebear into a line that never felt compromised or divided, or in any way diverted from the founder's original message of strong, progressive femininity. So many of the label's commercial successes under his tenure – the Muse and Downtown bags, the Tribute pumps – already feel so much a part of the sartorial canon that fashion fans became fraught at the idea of them falling out of production with Pilati's departure.

When Slimane – erstwhile photographer and the man whose skinny silhouette at Dior Homme famously encouraged Karl Lagerfeld to go on a diet in the early Noughties – took over in March, his intention to break with the recent past was clear. The change of name to 'Saint Laurent Paris' was intended to recall the label's very first incarnation in the Sixties – instead, all it seemed to do was start a chain reaction in the summer that culminated in October with a show that many deemed disappointing, and some even desultory. Slimane reworked the Saint Laurent archive according to his own back catalogue: skinny suits and boho flashes, jewel-coloured gowns and scatterings of safari that were masterfully made but not immediately arresting.

Simons' debut at Dior earlier that week, however, signalled the rise of a new power in Paris. Dior, for so long at the forefront of fashionable fantasy by sheer dint of Galliano's brain, had lagged without anyone to steer the ship: what Simons presented, in elegantly worked holographic organdie that made up wrapped tops, tunics and delicately-printed bell skirts in homage to the founder's New Look line, was a restrained but feminine vision – one that entranced critics and cool kids, but also this label's decisively bourgeois fan base of customers.

And Sander's return to her own label this autumn felt like another smooth transition, an evolution of what Simons had instigated in her absence, with a retro-futurist nod to the work of Pierre Cardin and André Courrèges in a palette of rust and midnight. That's right, not red and blue.

If that didn't make for a tense enough segue into autumn, the announcement that Maison Martin Margiela would be creating a capsule for H&M in November worked shoppers into a frenzy; it came on the back of a collaboration with Versace earlier in the year, as well as a capsule by JW Anderson for Topshop in what was a strong year on the high street, despite Philip Green's daughter Chloe (of Made in Chelsea fame) making her debut this spring as a footwear designer at – you guessed it – Topshop.

Finally, the strangest trend of the year: the wedge/trainer hybrids popularised by French designer Isabel Marant and now copied ubiquitously. They're wrong – terribly wrong – but somehow also just right (for another month, perhaps). And the biggest fashion mishap? Angelina Jolie's rogue leg on Oscar night, crooked at the perfect angle and totally preposterous for that.

But back to Marc Jacobs and his Louis Vuitton steam train – all aboard for 2013!

@Camillalong I have genuinely just come across a book entitled, "Fifty Hats that Changed the World"

Camilla Long, journalist

@LibertyLndnGirl Nothing makes me crosser than people who think that in my job I just flit around air kissing & stroking my high heels

Sasha Wilkins, fashion blogger

@hilaryalexander Reason why London Fashion Week is different+sustains a 20 billion industry is because WE CAN DO IT, Stella MC's show was pure London

Hilary Alexander, fashion writer

@stephenfry Are onesies the new Twilight? I've put in a order for a cheetah and a monkey. Dare I use them in the street I wonder?

Stephen Fry, broadcaster

@PennyRed Must remember that whatever Cosmopolitan and my mother say, winning at clothes is not the same as winning at life. #deadline

Laurie Penny, columnist

@Lorraine ELLE Witnessing fashion history@Dior. To beautiful and breath taking to describe by tweet. It wd do such a show disservice

Lorraine Candy, Elle editor

@KarlLagerfeld I think tattoos are horrible. It's like living in a Pucci dress full-time

Karl Lagerfeld, designer

@susiebubble When will the fetishisation of far-removed industries (fishing, mining, farming, wood-chopping) in menswear end?

Susie Bubble, blogger