Today, 13th March 2023, marks the 90th anniversary of one of several extensions of the Piccadilly line, with two new stations opening at Southgate and Oakwood.

The Piccadilly line first opened in 1906 with a line from Hammersmith to Finsbury Park, with plans to expand northwards blocked by the Great Northern Railway. However, the terminus at Finsbury Park was hopelessly overcrowded with trams struggling to carry people northwards, and in 1929, approval was given for an extension up to Cockfosters.

It took a couple of years to dig the tunnels from Finsbury Park to Arnos Grove and that extension opened in September 1932 without any ceremony.

On 13th March 1933, a second extension was completed, opening up stations at Southgate and Oakwood, although at the time it was called Enfield West.

As part of the 90th-anniversary celebrations, yesterday there were tours of Southgate tube station to show off Charles Holden’s genius design.

Southgate Station

Southgate station is one of the most distinctive tube stations on the network, with its famous low-rise circular design finished off with the Tesla-coil style finial. The station was nearly called Chase Side or Southgate Central, but eventually settled on plain Southgate, apart from a couple of days in 2018.

As you might expect from the architect, Holdon paid a lot of attention to details, such as the circular ripples in the ceiling where the pole holds the roof up, to the circle in the ground tiling, and even building a separate circular road junction space outside where one wasn’t really needed. But it looks better for it.

There are a lot of nice touches here, such as the surviving passimeter box in the middle, where people used to check tickets — a function now carried out by the ticket barriers, and they used bronze panels when the escalators were replaced, rather than the grey steel that escalators are usually lined with. Even the plastic bin bag holders have a hint of heritage about them.

What was a surprise is that this station has a concealed tunnel.

Designed to provide storage space for engineering works, the tunnel runs between the two railway tunnels and provides direct access to the railways (through locked gates of course), and as much as the architecture outside delights, a bit of unfinished raw tunnel is always a delight to see.

So much so that the tour guides had to be rather stern with getting people to leave!

There are plans to give the station a bit of a touch-up later this year to restore some of the heritage that needs attention, including restoring the original golden ball at the top of the Tesla-coil finial.

It’s good though that TfL staff give up their time to volunteer as tour guides, and share their own fascination with the history of the London Underground.

Oakwood station

Further up the line is the second station to open 90 years ago — at Oakwood.

In a way, this looks very different, but feels familiar. It’s a much larger ticket hall, with a tall glass lined space and flat ribbed concrete roof. More of a dominant box than the low lying Southgate station, it was built to be a landmark in the then empty countryside.

Down on the platform, there’s a long shallow roof supported by some impressively thin concrete arms that splay out subtly and the glazing in the middle prevents the low roof from feeling oppressively low.

The railway viaduct

However, there’s something else worth looking at for this extension – and that’s a large viaduct.

When the Piccadilly line runs north of Arnos Grove it needs to cross a long shallow valley to get to Southgate, so they built a brick railway viaduct through the valley. Something you won’t really notice from inside the train, but very much worth a visit to see from the ground. Fortunately, it’s easy to get up close as they kept the land around the viaduct open as a public park.

So happy birthday, not just to two architecturally famous tube stations, but also to the less well known but really should be, railway viaduct.