[zfnmxt]

> if the baseline chance of delay is 10%, engineering works add 25%, strikes add 35%, and bad weather adds 20%, then when all these problems happen, there's a 90% chance your train will be delayed.

What if signal failures "add" 15%? Then all factors combined would mean that there's a 105% chance your train will be delayed!

Adding up probabilities like this doesn't make sense. If you simplify these things as independent events, the probability of delay is just the 1 minus the product of all the probabilities of each event not happening (i.e., 1 - P(event)).

As for the article---I think you really undervalue your time and the price of inconvenience. I can see how you can romanticize it as a nice way to get things done, but (dealing with) train delays is hardly distraction free and is full of forced setting changes and (very) shit working environments (like waiting on a platform). This is a bad deal, even if it's free. Money is there to to be spent; this is a instance in which to spend it, moral/ethical/fraud concerns aside.

But hey maybe you're a Von Neuman type and thrive in cacophony and chaos.

[WindyMiller]

I think you really undervalue the pleasure of getting one over on our awful train system, and also overestimate how much money the young people of the UK have access to.

[ValentineC]

> As for the article---I think you really undervalue your time and the price of inconvenience. I can see how you can romanticize it as a nice way to get things done, but (dealing with) train delays is hardly distraction free and is full of forced setting changes and (very) shit working environments (like waiting on a platform).

By delays, I think the author meant that they get on a train, then sit in it for ~5 hours, with the option of paying roughly twice the price for first class [1].

As someone who frequently uses their laptop on public transport too, this sounds like a great way to either get things done or pass time.

[1] https://www.avantiwestcoast.co.uk/travel-information/onboard...

[Doctor_Fegg]

Though the problem is that delayed trains are often overcrowded trains. And overcrowded trains are not conducive for doing work on a laptop, unless you like sitting on the vestibule floor outside the toilet door with your laptop on your knees.

[sveme]

Sir, this is an Englishman writing; he‘s obviously taking the piss.

[MathMonkeyMan]

Your comment made me wonder. 65% chance of delay.

    >>> s = 'if the baseline chance of delay is 10%, engineering works add 25%, strikes add 35%, and bad weather adds 20%'
    >>> pb = 0.1
    >>> pe = 0.25
    >>> ps = 0.35
    >>> pw = 0.2
    >>> p = 1 - (1 - pb)*(1 - pe)*(1 - ps)*(1 - pw)
    >>> p
    0.649

[irjustin]

Agreed, but also where did those %'s come from? Seems like thin air so it's really all a gamble at this point.

[Aeolun]

Most of these trains are one and done things straight from the departure station to London?

The only experience I have was taking them in the other direction though, because I opted for a flight instead of dealing with it again to go back to London.

Was a new experience booking a train ticket and seeing a quote of £250. I thought the machine was broken.

[tempfile]

For small probabilities it works :)

1-(1-p1)(1-p2) = p1+p2-p1p2

and a similar formula holds for more terms. so neglecting terms of order p^2 gives the form in the article

[sebastiennight]

For probabilities (much) smaller than 10%, sure.

But adding 10%, 20%, and 35%, is already a pretty bad start. The error rate becomes huge. (in the article example, the 10% estimate of chances of being on time is ~3.5 smaller than the actual 35% correct result).

Being wrong by half an order of magnitude, is being quite wrong :)