Last November, TfL began trial operations on the Elizabeth line.
As part of the upcoming phase, large-scale exercises will be conducted across the new railway line.
Last month, work progressed at the two new stations, with upgrades carried out for the completion of the new railway.
The new Alstom train software was deployed on trains, along with the commissioning of the modern Siemens signalling software for the railway.
The control communications solution and the tunnel ventilation system were also modernised.
Several entities, such as London Underground and TfL, MTR Elizabeth line, Network Rail, and the emergency services, are jointly collaborating to respond to the trial exercises.
Emergency services cover the British Transport Police, London Fire Brigade and London Ambulance Service.
Some of the exercises are responding to train, signalling, platform screen door as well as track simulations.
For ensuring mileage and reliability, trains have been operating through the tunnels since last May.
After opening, the Elizabeth line will run 12 trains per hour through the central portion of the railway.
In a statement, TfL said: “The Elizabeth line is extremely complex, and the Trial Operations phase will continue until it is clear that the highest levels of safety and reliability are in place before the railway can open to customers.”
The Elizabeth line, which spans between Paddington and Abbey Wood, is projected to improve transport connections, minimise travelling times, as well as provide extra capacity.
It will also offer better accessibility with open new stations and walk-through trains.