What is one of the uses of train batteries?

Train batteries play a crucial role in several functionalities within the train systems. One significant use of train batteries is for operating systems that require power when the main power supply isn't available.

In particular, raising the pantograph after the train has been stabled is a function that relies on battery power. The pantograph needs to be raised to connect to overhead power lines when the train is stationary and requires immediate access to electrical power for systems that run on the train's main power supply upon departure. This ensures that the train can quickly reestablish connectivity to the power source without delay.

Other functions like powering air conditioning systems, controlling braking systems, and powering train signals typically rely on the main electrical systems of the train or have dedicated power relations, which may not primarily depend on battery power. Therefore, the operation related to the pantograph being raised after the train has been stabled is a clear illustration of one important and practical application of train batteries.