How does the passenger reservation system of Indian Railways work?

Indian Railways is one of the large-railway network in the world. Do not read it as the best railways in the world. Until 1990’s (1996) the reservation system was completely manual and on the paper. There was computers in use to aid the process. Every railway-station used to have a quota for every-train that halts in the station. The bigger the railway station and the surrounding areas, the more number of berths the quota contains. Either public used to walk to the manual-reservation counter or used to book via a travel-agent. The tickets were, as far as I know, were small cards of size 2.5cm x 5cm (close to 1 inch hight and 2 inch width), with a thickness of  close to 2mm, with the background in pink colour, with source and destination pre-printed and date of journey impressed (embossed) on the ticket at the time of buying. Cancellation of the tickets was also allowed, but at the counter only.  Since it was on the paper registers, the name of the passengers could be altered at any time.

Computer based reservation system was introduced in the late 1990’s to reduce the paper work and complexity involved in the passenger reservation management. In the late 2000’s, Indian-railways made web-based reservation system available to public.

How does computer based reservation systems work?

Computer based reservation system consists of two parts.

Servers and Clients.

Servers:

There will be multiple servers maintained to share the load of the traffic from clients. Servers are generally located in Mumbai and Delhi and only system-administrators will have direct (back-end) access to the servers.

Servers consists of three parts.

  1. Storage System – typically oracle database — responsible for storing the ticketing information and transactions w.r.t. booking.
  2. Server Application — responsible for authentication, ticket price calculation, availability and filtering logic and financial-transactions.
  3. WebServer — responsible to displaying User-Interfaces at the clients.

Clients:

Clients are generally light-weight and they do not store (not even cache) any information. Clients are typically the terminals used at railway reservation counters and web-browsers used by the public.