There's a reason for the uniquely complicated layout of the Northern line. It was created in the 1920s by the merging of two different railways. Unfortunately, knowing this fact doesn't make it any easier to navigate, and even locals end up on the wrong branch from time to time.
The bifurcated nature of the Northern line also means there's often more than one way to reach your destination — and not all routes are equal.
Fast and slow branches
Let's assume you're coming up from the south of London. Obviously if you’re going to the West End you’ll need a train that goes via Charing Cross, and if you're heading for the City you'll want Bank branch.
But what if you're heading to a more northerly destination? The two routes conjoin at Camden Town, before dividing again into the Edgware and High Barnet branches.
As long as your train is going to the right eventual destination, it might seem to make no difference which route you take through the centre. In fact, catching the right train can shave valuable minutes off your journey.
According to TfL's online timetable, Bank branch trains take 21 minutes to cross the centre, while the Charing Cross branch gets to Camden a full five minutes earlier.
So it's well worth waiting an extra minute or two to get a Charing Cross train, if one's coming. Even if the next one isn't going your way — for example, if it's High Barnet-bound but you need an Edgware train — it's a good idea to jump on and change trains at Camden Town. You certainly won’t be worse off, and you've a good chance of intercepting an earlier Edgware train coming via Bank.
It's a similar story in the other direction. Officially it takes 21 minutes to travel from Camden Town to Kennington via Bank branch, versus — well, actually TfL reckons it’s only 15 minutes heading south via Charing Cross.
Quirks in the timetable
It does seem a bit odd that travelling south would be faster than going north, and that's not the only little oddity in the schedule.
We mentioned that travelling from Camden to Kennington via Bank officially takes 21 minutes — but if your train's terminating at Golders Green, or turning off to Mill Hill East, then TfL says it'll take you an extra minute to cross London.
Since there are only seven Mill Hill services a day going through the city, we can see how a little extra time might be needed for everyone who's been waiting to crowd on. But as for Golders Green, we're stumped.
Dig into the timetable and you'll find other similar discrepancies, such as some trains taking three minutes to get from Mornington Crescent to Camden Town, while others do it in two.
That said, amid the daily chaos of a transit system that transports more than three million people a day, such timetables are at best an approximation of reality. The Charing Cross branch may be faster than the Bank branch on average, but the length of any individual journey is far from predictable — as Northern line commuters will attest.
This brings us to an important point: TfL would have you believe that travelling from one station to another always takes exactly the same time, regardless of whether you do it at the height of rush hour or on a lazy Sunday afternoon.
Clearly, this isn't the case: trains make palpably slower progress at busy times, when scores of people are trying to crowd off and on at each station. So while the Charing Cross branch is officially the speedier route, it may not always the best choice in practice.
On a hot summer weekend, when the West End is crammed with tourists and the city is comparatively dead, that five-minute advantage is likely to be eroded away to almost nothing — plus, you'll have the joy of travelling in a sweltering, overcrowded carriage.
Still, knowledge is power, and now you know the truth. All things being equal, the Charing Cross branch is faster. So next time you're sitting on the platform, you can make an informed decision whether to hop on the next train that comes along, or wait it out and enjoy a swifter ride.