To get to work I usually take the London Overground train from Highbury to Kensington. It’s part of a rail line that orbits central London around four miles out, allowing people to move around the city while remaining within urban areas and steering clear of the centre. It spares me the ordeal of travelling through central London at rush hour, so I’m really glad it exists.

People who share a regular journey eventually form communities based around shared patterns of group behaviour rather than personal relationships. A well-known example from the Tube can be seen when people boarding the train stand aside to let others get off first – that’s a behavioural pattern that Tube travellers follow, and new travellers quickly learn. Lots of these little patterns exist among commuter communities which, despite being only temporary rush-hour formations, are communities nonetheless.

Most people only take one regular route, so may not notice the behavioural patterns that fleetingly bond them to their fellow travellers. But I’ve recently started taking another regular route, down to the City of London, which has got me thinking a lot more about this.

It’s a far shorter commute for me, only two stops. It’s also a more conventional “spoke-to-hub” commute: the route begins outside London and bores its way inwards to stop at Moorgate, in the city’s central zone. This is in stark distinction to the radial nature of the Overground route.

Over time I’ve started to notice how the patterns of the City community differ from those of the Overground. The most significant difference relates to overcrowding.

On Overground trains an unspoken rule is, “move down the carriage”. Travellers follow this rule silently – as space appears further down the carriage, people move up to leave space nearer the doors. When the rule is ignored and an unnecessary crush develops, the offenders are loudly admonished – “can you move down please!” – and things soon right themselves.

How the Overground handles overcrowding

But on the City commute things are different. A train pulls into the platform and there’s lots of space. But then you look at the  doorways, and it’s jammed solid – everyone has bunched up near the doors. You think, that’s not a problem; people will move. But this isn’t the Overground. The people in the doorways, already uncomfortably compressed, simply inhale sharply as you wedge yourself in next to them. The train is silent. No-one moves, and no-one is asked to move.

This community seems to have a different rule – “don’t rock the boat”. Shouting into the sheer silence would mark you as a lunatic. It’s a powerful rule: I’ve seen people abandon their attempts to board the train, choosing to wait ten minutes for the next one rather than cause a fuss by telling people to move into the empty space.

Suburbanites heading to the City stay in the doorways

How has the City community formed such different behavioural patterns than the Overground community? The routes use exactly the same trains, so it’s not carriage layout. And it’s not the suburban nature of the passengers – I’m an urbanite and I end up adhering to the pattern, as do others who get on at my stop. Some possible reasons are:

• The City community arrives at Moorgate, within walking distance of any office in the City, so many might never have to use the Tube. On the Tube, the authorities run frequent poster campaigns about how to behave – if they didn’t, the Tube (with its mixture of commuters, shoppers and tourists) would be sheer chaos. The Overground community is exposed to these campaigns but the City community, spared the ordeal of Tube travel, isn’t.
• My stretch of the City commute is underground so people don’t use mobile phones. This contributes to the oppressive silence: speaking aloud marks you out as a lunatic. But on the Overground, there’s a constant background babble of phone chat, which means it feels less strange to call out to other travellers.
• Everyone on the Overground is moving from one urban district to another, so most people have an “urban” rather than a suburban approach to personal space and group behaviour. They’re accustomed to being told to move on, get out of the way, budge up and so on.

These are only part of the story however. What these two communities have in common is that they exist only at rush hour, have highly transient memberships, and revolve around simple, unspoken rules of personal conduct. But they diverge from one another when it comes to behavioural patterns, for reasons that are numerous, complex and hard to fathom.