The point of a congestion charge (whether on driving or on public transport) is to alleviate the congestion 'punishment'.
As a mental model: congestion works a bit like an auction. Getting from A to B during rush hour brings people some benefits (otherwise, they wouldn't bother). Benefits differ between people. But that travel also costs, both in terms of fares and in terms of annoyance and perhaps delays.
So We can imagine every prospective commuter weighs their benefits against the costs. I say it works like an auction, because there's limited capacity, and the people who are willing to endure the most price + annoyance are going to 'win' the auction and will commute. Everyone else shifts their commute around or stays home.
The people you mention who 'have to' travel during rush hour are just the ones willing to bear the highest costs in our model, and thus they 'win' the auction. (Winning an auction isn't necessarily good..: after all, you have to pay the price.)
Having a congestion charge means different people can bid not just with their tolerance for annoyance and delay, but also with actual money.
So now people compare fare + congestion charge + annoyance against their benefits. Assuming benefits on the right side of the equation have stayed about the same, the breakeven point for 'annoyance tolerance' is going to be lower, just because the other part of the left side grew.
A similar example: if tomorrow your local Walmart was handing out free 20 dollar bills with every purchase, you can bet your hat that pretty soon the queues for the cashier at that shop would grow until the wait-in-line for the marginal customer cancels out the free 20 dollars. Keep in mind that the marginal customer isn't the average customer: the queue would mostly be made up of people who have more time than money.
Conversely, in our congestion charging scenario the winners of our auction will tend to shift towards the crowd that has more money than time (or tolerance for packed trains).
The nice thing about letting people bid with money is that afterwards someone else has the money and can spend it. When you bid with your capacity to endure frustration and delay, no one else gets any benefit from that. It's just a poor waste of society's resources.
The point of a congestion charge (whether on driving or on public transport) is to alleviate the congestion 'punishment'.
As a mental model: congestion works a bit like an auction. Getting from A to B during rush hour brings people some benefits (otherwise, they wouldn't bother). Benefits differ between people. But that travel also costs, both in terms of fares and in terms of annoyance and perhaps delays.
So We can imagine every prospective commuter weighs their benefits against the costs. I say it works like an auction, because there's limited capacity, and the people who are willing to endure the most price + annoyance are going to 'win' the auction and will commute. Everyone else shifts their commute around or stays home.
The people you mention who 'have to' travel during rush hour are just the ones willing to bear the highest costs in our model, and thus they 'win' the auction. (Winning an auction isn't necessarily good..: after all, you have to pay the price.)
Having a congestion charge means different people can bid not just with their tolerance for annoyance and delay, but also with actual money.
So now people compare fare + congestion charge + annoyance against their benefits. Assuming benefits on the right side of the equation have stayed about the same, the breakeven point for 'annoyance tolerance' is going to be lower, just because the other part of the left side grew.
A similar example: if tomorrow your local Walmart was handing out free 20 dollar bills with every purchase, you can bet your hat that pretty soon the queues for the cashier at that shop would grow until the wait-in-line for the marginal customer cancels out the free 20 dollars. Keep in mind that the marginal customer isn't the average customer: the queue would mostly be made up of people who have more time than money.
Conversely, in our congestion charging scenario the winners of our auction will tend to shift towards the crowd that has more money than time (or tolerance for packed trains).
The nice thing about letting people bid with money is that afterwards someone else has the money and can spend it. When you bid with your capacity to endure frustration and delay, no one else gets any benefit from that. It's just a poor waste of society's resources.