The Problem with Trains

Her train is travelling towards the oncoming trains as fast as they are coming towards her train, so she sees one every 30 seconds, not one every minute. Another way to look at it is this: If she catches the 9am train from London, the first train she will see is the 8am from Brighton arriving on the opposite platform. When she arrives in Brighton an hour later, the last train that she will see is the 10am as it departs. So that’s two hours’ worth of trains at one per minute, or 120 trains in all.