Under what condition may express trains make local stops?

Express trains typically adhere to a specific schedule that allows them to bypass local stops in order to maintain a quicker travel time for passengers who are traveling longer distances. However, there may be situations where express trains are required to make local stops. Rerouting due to cold weather plans is one such condition where express trains could be mandated to stop at local stations. For example, in situations where certain tracks may be disrupted or if service alterations are necessary for safety reasons due to weather-related issues, express trains may be directed to serve local stops to ensure that all passengers have access to the service they need.

In contrast, making stops during rush hour may not be typical practice, as express trains aim to help facilitate quick transit through high-density areas. A passenger request can often not override operational protocols for express services, given the primary aim of express trains to speed up routes. Emergencies can complicate schedules, but they do not universally dictate that express trains make local stops as a policy; they may divert or halt service entirely based on safety needs rather than stopping at every station.

Therefore, the condition involving rerouting due to cold weather plans most accurately addresses the operational flexibility that ensures passenger safety and accessibility during adverse weather conditions.