Most built environments rely heavily on stairs. While elevators and ramps both exist, many
designers choose not to use them. As of late 2020, only 29% of London's Tube stations were
step-free (80 out of 272), with work underway in 12 more stations.
Mind Your Step aims to provide step-free access to as many London Underground stations as
The objective is to decide how to best select the next batch of stations to be converted into
The purpose of this project is to maximize the number of step-free passenger journeys.
A total national budget constraint is fixed for the next batch of 12 stations, while the cost of
conversion to step-free depends on the station's category.
Also, the impact of service changes during a trip between two stations is omitted in the
Initially, the network's structure is generated, and the stations are classified by their type
(step-free or non step-free) and popularity (arriving / departing passengers). The journeys can
be identified as fully or partially step-free. Finally, the optimisation model is implemented in
Python, using NetworkX, Pandas and PulP.