Investigating ramp gradients for humps on railway platforms

Horizontal and vertical gaps between the train and the platform are a major safety concern for railway passengers, especially for disabled passengers. London Underground is implementing a programme to install platform humps to remove vertical differences between the train and the platform. In order to properly design platform humps, this study empirically investigated the effects of the design factors of the ramps, namely the slope and cross-fall gradients, on disabled passengers. The investigation consisted of two experiments: one where 20 participants were asked to walk on simulated slopes, and the other where 25 participants were asked to board or alight from the simulated train from or onto the slopes. The slope gradients tested were 3.0% (1:33), 5.2% (1:19) and 6.9% (1:14) with the cross-fall gradients 1.5% (1:67), 2.0% (1:50) and 2.5% (1:40). The results showed that the slope gradient does not largely affect the participants' performance of longitudinal walking on the slopes or their subjective safety evaluation, but would cause additional difficulty for them to board/alight from the train from/onto the slope. This suggests that train doors should not stop next to the ramp. There was little evidence concerning the effects of the cross-fall gradient. The results provide useful information for designing platform humps.