What is the function of apps labeled C?

The function of apps labeled C is to affect live train movement. This means these applications play a crucial role in the operational aspects of train management, including monitoring real-time train statuses, tracking delays, and adjusting schedules based on current conditions. By affecting live train movement, such apps can help ensure that train services run smoothly and efficiently, which is vital for maintaining punctuality and overall customer satisfaction.

Other choices may refer to important functions but do not directly relate to the primary operational role described. For instance, providing customer assistance, storing customer data, and facilitating ticket purchases are important components of the passenger experience but do not directly impact the live management of train operations. Thus, the focus on affecting live train movements distinguishes these apps' key operational role within Amtrak's system.