The Anonymous Widower

Why Do 21 And 141 Buses Always Come Together?

To get between my house and Moorgate station, I use either a 21 or a 141 bus.

During the day, both buses run at a frequency of about one bus every ten minutes.

As the buses take exactly the same route between Bank station and Newington Green, surely it would be logical, if the buses were timed on this section, so that the buses ran every five minutes.

But inevitably, a 21 and a 141 bus always turn up together, which generally means if you miss both, you have to wait ten minutes until another pair come along.

Surely, a bus every file minutes might encourage more people to use the buses.

October 6, 2021 - Posted by | Transport/Travel | , , , , , ,


  1. They probably are on a five-minute headway, but they tend to bunch together. An old mate of mine, who lives in the Barbican did his MSc thesis on this decades ago.

    Basically the first bus, spends longer at each stop picking up passengers, so the second bus catches it up. This increases as their journeys continue because the closer the second bus gets the less passengers [if any] at each stop and less time boarding and disembarking them, until it catches the first bus. The third bus is now nearly ten minutes behind the first two and spends even longer at stops perpetuating the problem onto the next pair.

    Still does not explain why they always come in threes…

    Comment by R. Mark Clayton | October 6, 2021 | Reply

    • There could also be a problem with the fact that 21s are Routemasters and the 141s are ordinary hybrid buses. I feel that a well-driven Routemaster with its three doors and two staircases could be quicker over a route.

      I always thought buses in London came in threes, after one got hit by a Nazi bomb in the Blitz, so they go in convoys for safety.

      Comment by AnonW | October 6, 2021 | Reply

  2. It’s because they are operated by different companies with their own separate control centre. The companies earn bonuses on an individual route by route basis. And even if it were one company tfl does not expect operators to space them out on common corridors, only to make sure they are spaced out according to the individual route excesss waiting time average.

    TfL rules!! You do make a very good point though, not sure how they can address it Unless tfl takes route control back in house.


    Sent from my iPhone

    Comment by Lawrence Wilson | October 6, 2021 | Reply

    • Thanks!

      On the railways, where Network Rail have a large say in the timetable, trains of different companies are often spaced out for customer convenience.

      Comment by AnonW | October 6, 2021 | Reply

    • But the one message that any bus passenger doesn’t like hearing is “this bus will stop here a short time to even out the service” (or words to that effect).

      The only customer focused way to increase frequency is to run more buses and to prevent boarding when buses are nearly full to reduce dwell times and maintain headway.

      I have long felt that journeys on frequently served routes could be faster if bus routes were arranged into “a” and “b” variants and skipped alternate stops (with key stops served by both “a” and “b” for interchange). Foregoing single seat travel for some in favour of better speed/reliability.

      Comment by MilesT | October 6, 2021 | Reply

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