When I last visited Wood Green underground station, I had forgotten my camera. This weekend, I had not only my camera but also the opportunity to go behind the scenes. The open day and guided tour was one of the events marking the 150th anniversary of the Underground. 
Nearly seventy years after the first Underground train ran between Paddington and Farringdon, the system had expanded enormously - but London had expanded too. Finsbury Park was then the northernmost point of the Piccadilly Line, but most disembarking passengers still had further to travel. With no underground trains, they needed to take a bus or tram, and the queues for these became notorious. Not only were they huge during rush hour, but competition for places on board was such that fights were not uncommon.
The much-admired Frank Pick, head of the Underground, convinced parliament of the need for a Piccadilly Line extension, and appointed Charles Holden as station architect. He had already designed stations for the Northern Line between Clapham Common and Morden, the Piccadilly Circus booking hall, and the Underground headquarters at 55 Broadway. Pick offered him a free hand for these new stations - as well as Wood Green, they included Manor House, Turnpike Lane, Bounds Green, Arnos Grove, Southgate, and Cockfosters. The extension opened in September 1932.
The stations share cream-coloured tiling, but each has its own accent colour; Wood Green's is, aptly, green. Influenced by the 'form follows function' maxim of modernist architecture, Holden produced a restrained design of clean lines and unfussiness. However, there are beautiful details such as the grilles, designed by sculptor Harold Stabler, which cover the ventilation system outlets. Those in Wood Green show a rural scene with a deer.
A more sraightforwardly practical feature, added for the first time, was the 'suicide pit' between the rails. Originally a drainage feature, it provides a space where someone who falls onto the tracks might lie, safe from both the train and the live line. Happily, the open day provided a much safer way to get level with the tracks: from the safety of the maintenance area.
A door was held open by an old insulator. Recycling in action!
Another area not usually open to the public is the escalator control room. Here, the workings of the escalators, their motors and control systems were visible. This was a reminder that there's a lot more to their operation than the emergency stop button which is all we usually see!
Even on the platforms, the tour highlighted details which normally go unnoticed. I particularly liked this letterbox, tucked under the roundel at ground level.
Finally, among the architecture and engineering, something rather more frivolous also caught my eye!
