Shedding followersJust north of Queen’s Park station on the Bakerloo line, you experience something I’m pretty sure you can’t do anywhere else on the Underground.

You get to pass through a carriage shed.

That might not sound particularly tremulous, and I grant you it’s not on a par with the kind of sensory overload you endure on a ghost train or enjoy on a seaside tram. But it shares the same novelty value. And if you’re in the mood, there’s a tingle of excitement to be had from peeping inside somewhere it feels you’re not meant to go.

She said, there's something in the train shedIf you’re heading north, you trundle through entrance 21, past a very old (but still perfectly legible) 10 MILES AN HOUR warning sign. Once you’re inside, look out of the right-hand windows and you’ll probably see a couple of trains sitting in berths 22 and 23, not really doing much. You’ll possibly spend a minute or so doing the same, before your train is given a green signal to carry on up the line to Kensal Green: nemesis of all connoisseurs of The London Game.

If you’re heading south you’ll probably come through number 24. Whichever track you end up on, however, the effect is the same: a moment of anxiety as you conclude you’re sitting in a train that’s been sent to the sidings, followed by a longer moment of embarrassment when you realise your mistake.

Two little ducksWhen you pass through the shed, I wonder under whose jurisdiction you fall. I can imagine there are issues over “conveyance”, with unions and management holding urgent negotiations to agree terms of safe passage. I hope there are “lucky” entrances, and that superstitions have built up around particular numbers. In bingo lingo, would you prefer two little ducks or a knock on the door?

For shed followers, you probably can’t beat arguing about something like this. For shedding followers, you certainly can’t beat writing about something like this.

AmershamdyIn the top left-hand corner of the Underground map, the short, stubby branch lines that run to Amersham and Chesham sit there like a two-fingered salute to the empty space beyond.

You think we’re going to come any further into Buckinghamshire, they pout. Well ha ha, we’re not. You’re going to have to come to us. We’re not coming to you.

Our loyalties and life support lie south-east, in the metropolis, not north-west, in the middle of nowhere. We’ve planted our toes beyond your boundaries, and we’re not budging. So there. Cue enormous raspberry.

But this – adopts Adam Curtis voice – is a fantasy.

Trains do run beyond Amersham, despite it appearing on the map as the end of the line.

They run deep into Buckinghamshire, albeit not under the purview of Transport for London. They do, however, run on tracks that once belonged to the Underground – tracks that caterpaulted out of the city in the hope of one day becoming part of a hilariously ambitious uber-network that would link northern England with the continent.

Now look at it.

Red hat not picturedThat’s the very last roundel passengers on the mainline get to see.

No longer does the Metropolitan sneak its way up to Aylesbury. That ended in 1961. It used to puff its chest out even further, stretching the elasticity of the system to breaking point in order to poke a smoke-filled nose into Verney Junction. That ended in 1936.

I like the way things are now.

I’m taken with the frontier feel of Amersham – a place, before I moved to London, I knew only as the one and only sighting of the dreaded Red Hat of Pat Ferrick.

It’s just far enough out of London for the Underground to venture and still allow you to sense the faint pulse of the city. It has a rather attractive trace of desolation that never threatens to develop into full-blown abandonment.

Travelling up the Metropolitan line, you’ve unwound your ball of purple wool as far as it can go, threading it all the way from Baker Street through Wembley, Harrow, Pinner and Rickmansworth.

Now the wool has run out. But one tug of the strand and you can find your safely way back home again.

British Rail lives onSure, there’s always platform 1, with its bittersweet invocation of British Rail above its promise of the faintly exotic-sounding Great Missenden and Wendover.

But platform 3 is where London begins, and where the Underground devotee can affirm their love affair all over again.

You can stare all you like at the countryside beyond the buffers. But “in those wet fields the railway didn’t pay. The Metro stops at Amersham today.”

In those wet fields the railway didn't pay

Peace in the 'Valley

A bit of an atypical choice, this. I’ve included it not because of something, but despite.

What’s great about Roding Valley is that despite being the least-used station on the entire Underground, it continues to exist. Moreover, it does so – to paraphrase the Bluetones, another outer-London treasure – with a little charm and a lot of style.

Don’t come here looking for architectural wonder or lashings of imaginative design. Give Roding Valley a miss if you’re out to sample the Underground at its aesthetic finest. Do come here, however, if you want a sense of the network going about its business modestly, extremely quietly, and in the absence of arithmetical tumescence.

Build a station and they will come

Build a station and they will come. Even if it’s around 220,000 people a year. That’s an average of 602 a day – roughly the number who move through Victoria Underground station every 90 seconds.

Compared to central London, every time is off-peak time at Roding Valley. But pass this way in the dead of morning, or in the hollow of an afternoon, and you might not see another soul during the 20 minutes you can spend waiting for a train. I didn’t. And I rather enjoyed it.

You can also, if you want, pretend the place belongs to you. I did. And I rather enjoyed it. Though it’s impossible to ever completely relax and, say, start dancing along the platform. Cameras are in evidence, connected to a location miles away where people are present, watching for unfamiliar faces cutting some rug or loitering to take pictures.

If you’re after that certain kind of stillness that only dwells in barely-breathing stations that are best known for making footnotes rather than headlines, there can be fewer more pleasant locations.

And even if you never have cause to visit, it’s awfully nice to know that Roding Valley is there. Despite… well, despite pretty much everything.