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Notes / Design Interview Problems / Design IRCTC Train Booking (Route-Segments, RAC, Waitlist, Charting)
Track 5 · Design Interview Problems

Design IRCTC Train Booking (Route-Segments, RAC, Waitlist, Charting)

How a nationwide railway reservation engine allocates overlapping route segments on a single berth, manages RAC and waitlist state transitions, absorbs the 10:00 AM Tatkal storm, and prepares final charts four hours before departure.

How to allocate berths across multi-station route segments, manage RAC side-lower berth sharing and waitlist promotions, absorb 50,000 requests per second at 10:00 AM Tatkal opening, and run the 4-hour charting engine with family clustering and automated refunds.

Interview problem45 min read
On this page
  1. Why this problem is hard
  2. What are we building?
  3. Entities, API and numbers
  4. Building it up, one step at a time
  5. Where it gets hard
  6. Failure modes at a glance
  7. The whole picture
  8. How interviewers judge this
  9. Questions that come next
  10. Saying it out loud in 45 minutes
  11. Sources and assumptions