Train Platform Management System
What is the Train Platform Management System Problem?
Section titled “What is the Train Platform Management System Problem?”Design a Train Platform Management System that assigns trains to platforms based on availability, manages schedules, tracks platform states (Available, Occupied, Maintenance), prevents double-booking, calculates turnaround time, tracks platform features, provides real-time updates, and handles emergency situations like delays and platform reassignments.
In this problem, you’ll design a system that coordinates platform assignments, manages time-based schedules, handles state transitions, and ensures real-time synchronization across multiple systems.
Problem Overview
Section titled “Problem Overview”Design a comprehensive system that manages train platform assignments, schedules, states, and real-time notifications while preventing conflicts and handling emergencies.
Core Requirements
Section titled “Core Requirements”Functional Requirements:
- Platform Assignment: Assign trains to platforms based on availability, ensuring no double-booking occurs.
- Schedule Management: Track and manage train arrival and departure schedules with time slots.
- Platform States: Manage platform states: Available, Occupied, and Maintenance.
- Conflict Prevention: Prevent double-booking of platforms by checking availability and schedule overlaps before assignment.
- Turnaround Time: Calculate time between train departure and next train arrival on the same platform.
- Platform Features: Track platform features (length, facilities like escalators/elevators, accessibility) and match with train requirements.
- Real-time Updates: Provide real-time updates to displays, mobile apps, and other systems when platform status changes.
- Emergency Handling: Handle train delays and automatically reassign platforms when necessary.
- Feature Matching: Match platform features (length, accessibility) with train requirements before assignment.
- Notifications: Notify relevant stakeholders about platform status changes, assignments, and releases.
Non-Functional Requirements:
- Object-Oriented Design: Clear separation of concerns with well-defined roles for each class.
- Modularity: Easy to add future enhancements like new assignment strategies, platform features, or notification mechanisms.
- Thread Safety: Platform assignments and schedule updates must be thread-safe to handle concurrent requests without race conditions.
- State Management: Maintain a clear state flow from Available to Occupied to Available, or Available to Maintenance and back.
- Reliability: Core scheduling logic should be robust, testable, and maintainable over time.
- Extensibility: Support for future features like predictive scheduling, load balancing, or integration with external systems.
What’s Expected?
Section titled “What’s Expected?”1. System Architecture
Section titled “1. System Architecture”The system coordinates platform assignments through a central manager that uses strategies and maintains platform states.
2. Key Classes to Design
Section titled “2. Key Classes to Design”classDiagram
class PlatformManager {
-Map~String,Platform~ platforms
-PlatformAssignmentStrategy strategy
+assignPlatform(trainId, times)
+releasePlatform(trainId)
}
class Platform {
-PlatformState currentState
-List~ScheduleEntry~ scheduleEntries
-List~PlatformObserver~ observers
+assignTrain(train, times)
+releaseTrain(train)
}
class PlatformState {
<<interface>>
+handleAssignment()
+handleRelease()
}
class PlatformAssignmentStrategy {
<<interface>>
+assignPlatform()
}
class PlatformObserver {
<<interface>>
+onPlatformStateChanged()
+onPlatformAssigned()
}
PlatformManager --> Platform
PlatformManager --> PlatformAssignmentStrategy
Platform --> PlatformState
Platform --> PlatformObserver
PlatformState <|.. AvailableState
PlatformState <|.. OccupiedState
PlatformState <|.. MaintenanceState
PlatformAssignmentStrategy <|.. ClosestAvailableStrategy
PlatformAssignmentStrategy <|.. BestFitStrategy
PlatformObserver <|.. DisplayObserver
PlatformObserver <|.. MobileAppObserver
System Flow
Section titled “System Flow”Platform Assignment Flow (State Transitions)
Section titled “Platform Assignment Flow (State Transitions)”
Key Design Challenges
Section titled “Key Design Challenges”1. Preventing Double-Booking
Section titled “1. Preventing Double-Booking”How do you ensure that two trains are never assigned to the same platform at overlapping times?
Solution: Use Schedule Entry Overlap Detection. Before assigning a platform, check if the new time slot overlaps with any existing schedule entries. The ScheduleEntry.overlaps() method checks if two time slots conflict by comparing arrival and departure times.
2. Matching Platform Features with Train Requirements
Section titled “2. Matching Platform Features with Train Requirements”A train requiring accessibility features cannot be assigned to a platform without those features.
Solution: Use Feature Matching Logic in PlatformFeatures.matchesTrainRequirements(). Check if platform length accommodates train length and if platform has required accessibility features before assignment.
3. Real-time Updates Across Multiple Systems
Section titled “3. Real-time Updates Across Multiple Systems”Multiple systems (displays, mobile apps, analytics) need to be notified immediately when platform status changes.
Solution: Use the Observer Pattern. Platforms maintain a list of observers and notify them when state changes occur. This decouples the Platform class from specific notification implementations and allows multiple systems to observe the same platform.
4. Handling Emergency Situations
Section titled “4. Handling Emergency Situations”When a train is delayed, the system needs to reassign it to a different platform if the original platform is needed by another train.
Solution: Implement Delay Handling in PlatformManager.handleDelay(). Release the train from its current platform, then attempt to assign it to a new platform. If reassignment fails, keep it on the original platform.
What You’ll Learn
Section titled “What You’ll Learn”By solving this problem, you’ll master:
- ✅ State Pattern - Managing complex state transitions (Available → Occupied → Available, or Available → Maintenance).
- ✅ Strategy Pattern - Implementing swappable assignment algorithms for different operational requirements.
- ✅ Observer Pattern - Decoupling notification logic from platform management for real-time updates.
- ✅ Concurrency Control - Using locks and synchronization to prevent double-booking and race conditions.
- ✅ Schedule Management - Handling time-based conflicts and calculating turnaround times.
- ✅ Feature Matching - Validating platform capabilities against train requirements.
View Complete Solution & Practice
Section titled “View Complete Solution & Practice”Ready to see the full implementation? Open the interactive playground to access:
- 🎯 Step-by-step guidance through the 8-step LLD approach
- 📊 Interactive UML builder to visualize your design
- 💻 Complete Code Solutions in Python, Java, C++, TypeScript, JavaScript, C#
- 🤖 AI-powered review of your design and code
Related Problems
Section titled “Related Problems”After mastering the Train Platform Management System, try these similar problems:
- Parking Lot - Similar resource allocation with concurrent access.
- Hotel Management System - Similar booking and schedule management.
- Movie Ticket Booking System - Similar conflict prevention and state management.