Statement: Ten coaches of a passenger train derailed, blocking both pairs of railway tracks.\nCourses of Action:\nI. Railway authorities should immediately send men and equipment to clear the tracks.\nII. Divert all trains running in both directions to alternate routes.

Introduction / Context:
A major derailment has fully blocked bi-directional traffic. Immediate response must focus on rescue (if relevant), clearance, and maintaining network throughput via diversions.

Given Data / Assumptions:

• Both track pairs are blocked.
• Passenger and freight schedules are affected.

Concept / Approach:
Sending crews and heavy equipment (I) is essential for clearance and restoration. Simultaneous route diversions (II) maintain continuity of service and prevent cascading delays and yard congestion. Both measures are standard incident-management practices.

Step-by-Step Solution:
1) Dispatch cranes, rescue, and engineering teams (I).2) Activate control rooms to reroute trains and issue public advisories (II).3) Resume normal service after safety certification.

Verification / Alternative check:
Railway SOPs pair on-ground clearance with traffic management to minimize systemic disruption.

Why Other Options Are Wrong:
Only I or Only II leaves either clearance or continuity unaddressed; Either/Neither misread the comprehensive need.

Common Pitfalls:
Attempting to keep trains on blocked sectors; delaying diversions.

Final Answer:
Both I and II follow.