25 Jun 2011
Station dwell times
Station dwell times can have a big effect on the overall performance of a railway, especially a busy commuter routes. The old slam door trains had doors spaced two metres apart, which made for fast boarding and alighting, and passengers used the open doors to provide support over the gap between the platform and the train.
Much of Britain's railway system was built when railway carriages were under ten metres long, which meant that there was never much of a gap even at sharply curved platforms. In combination with the high platforms that were standard in Britain, getting on and off trains was easy. But nowadays, carriages are twenty metres long or more, which means there can be a significant gap. Worse still, the tracks are now more sharply tilted on curves to allow for higher speeds.
This leads to the situation here at Clapham Junction, where there is a huge gap between the platform and the train. Apart from being a danger, passengers take extra care and extra time to get on and off the train, which extends the station dwell time.
Attempts have been made to help the situation. Modern trains have lower floors, and the doors are as close to the bogie centres as possible, given the 1:3/2:3 layout, as in the Electrostar train above, which is also supposed to improve station dwell time. Matters are no better with the mark 3 stock with end doors, but in that case the problem occurs at convex platform faces rather than concave ones as in the picture.
Never mind the gap
We really are at the point where new stock should be fitted with retractable steps, so that there is no gap to mind. It would also be possible to provide retractable handrails at the doorways to facilitate boarding and alighting. Retractable steps are a standard feature in new trains on the continent
These items would of course come at a cost, but the benefits of safety and reduced station dwell time would surely be worth it. With an ageing population, will soon be a necessity if the railway is to be accessible to as many people as reasonably practicable.