notverydeep
Member
- Joined
- 9 Feb 2014
- Messages
- 886
Any passenger on a train (for all but the very shortest journeys) wants to have a seat and any passenger wanting to make a train journey does not want to be left behind. For those specifying rolling stock these are clearly competing needs: the more seats you have the more the first desire can be satisfied, but seats mean each passenger occupies more space and the capacity of the train is lower than it would be if there were fewer seats. At busy times on busy routes, the chance of being left behind when the train is full will be greater. So the specifier must evaluate a trade off. What is the benefit of a greater seating capacity versus the benefit of reducing waiting times, by lowering the chance of being left behind.
For a fixed frequency, the benefit of being in a seat increases with average journey length as some passengers will experience the downside of having to stand up for longer. So the longer the average passenger journey, the greater the value of the extra seats that can only be accommodated by having at least some transverse seating. The chance of being left behind will tend to only make a difference at the height of the peak time, whereas having extra seats will add benefit even at off peak times on the busiest sections as the seating capacity is inevitably somewhat lower than the total capacity including standing spaces.
Looking at rolling stock built recently, the Elizabeth line and Metropolitan lines have longer average journey lengths than say the Victoria line or Circle line and so for former, some transverse seats were the best trade off and thus specified, even though this results in a lower capacity than would be the case with only longitudinal seats, where other lines with trains of similar age have no transverse seats. There can be marginal cases, for example the District line which could have gone either way, but having the flexibility of a common fleet with the Circle and H&C made the longitudinal seat option the best choice.
For a fixed frequency, the benefit of being in a seat increases with average journey length as some passengers will experience the downside of having to stand up for longer. So the longer the average passenger journey, the greater the value of the extra seats that can only be accommodated by having at least some transverse seating. The chance of being left behind will tend to only make a difference at the height of the peak time, whereas having extra seats will add benefit even at off peak times on the busiest sections as the seating capacity is inevitably somewhat lower than the total capacity including standing spaces.
Looking at rolling stock built recently, the Elizabeth line and Metropolitan lines have longer average journey lengths than say the Victoria line or Circle line and so for former, some transverse seats were the best trade off and thus specified, even though this results in a lower capacity than would be the case with only longitudinal seats, where other lines with trains of similar age have no transverse seats. There can be marginal cases, for example the District line which could have gone either way, but having the flexibility of a common fleet with the Circle and H&C made the longitudinal seat option the best choice.