Imagine a bucket with water in it. It’s got a hole in the bottom and a tap above it. Depending on how big that hole is, and how much the tap is flowing, there’s some level of water that stays the same.
In some ways train stations hold true to this analogy. Trains act as the ‘hole’ in the bucket, letting people out. The ticket gates are the ‘tap’ above the bucket, letting people in. Then inside, there’s some extremely complicated water. People are moving around, coming and going from different platforms, and leaving at varied rates.
What’s being described is called steady state. With both the water and the people in the station, there’s a certain amount that remains unchanging. The thing that’s different is that the number of people in the train station affects how long it takes you to get from the ticket gate to the platform. In turn, the number of people on the platform affects how quickly you can get on the train. If there’s always a lot of people in the system, this can cause issues.
Encircle aims to reduce the steady state – but it’s not entirely clear yet how best to do this. Is it optimal to wait for every single person to get on a train (which is the current practice in place on Sydney platforms)? Or is it better to reduce the time trains spend at stations, and send them through more regularly? The best way to test this is to simulate each of these situations. From that, it’ll be more clear what the best direction may be.