The benefits of automated metros are well-known, apart perhaps from the higher speeds that automation brings.
Driverless metros, which are becoming increasingly common around the world, generally have low operational labour costs as well as high passenger capacity. But automation also has a lesser-known advantage: speed. Not only can computer-controlled trains drive more closely together, but they are also faster. The difference appears to be substantial, perhaps as much as 20 sec per station.
The biggest determinant of average metro speed is the station spacing, with those further apart allowing higher average speeds. However, driverless lines are fast even taking this into account. London Underground stations have a mean distance of about 1·25 km between them, and trains reach an average speed of 33 km/h. The Tokyo metro has the same inter-station distance and an average speed of around 30 km/h. In contrast, the driverless København metro has a scheduled average speed of about 35 km/h, with only 1 km between stations. Vancouver’s SkyTrain is also fast for its station spacing: the Expo Line averages 45 km/h with 1·5 km between stations, while the Canada Line averages 35 km/h with 1 km.
It is not just metros built as driverless that are fast. Paris metro Line 1 opened in 1900. With a minimum curve radius of 40 m and an average of 700 m between stations, it could never achieve a high average speed. Following the line’s automation, carried out in 2007-12, the average speed rose from 24·4 km/h to 30 km/h. Dwell times are rigidly set at 30 sec, and the timetabled average speed of 29 km/h is close to the theoretical maximum that can be achieved with the station spacing, based on current rolling stock acceleration rates.