Up to a million people use the two lines every day.
The union is fighting over a number of agreements it says bosses are breaking, centred on the workers’ right to be respected at work.
Aslef district organiser Finn Brennan said, “Our members will not tolerate a situation where vulnerable people leave sickness review meetings in tears and drivers with years and years of good and long service are threatened with disciplinary action for a delay of 33 seconds in leaving a terminus.”
At rush hour there was no service on the
The 24 hour strike is set to continue until midnight.
Aslef is currently in talks with bosses, and has warned it could call another strike on Wednesday 17 September.