What is PNR?
Full form of PNR is Passenger Name Record, a unique 10-digit number which is provided against every train ticket that is booked across India. Each PNR numbers provides a variety of information to ticket-holder(s).

The PNR Status information includes ticket booking status (confirmed/waiting list/canceled), departure and arrival time, details of the train, seat number, fare paid by the passenger for the seat. When group booking is done, then a single PNR may be provided to up to 6 passengers.

How to check IRCTC PNR status online?
To check PNR status, follow these steps:

Find 10-digit PNR number on top left of your IRCTC train ticket.
Enter the PNR No. of your ticket and click "Get Status".
Your PNR Status will show up with information regarding your train ticket booking.
www.indianrail.gov.in
This is an official portal designed by CRIS (Centre for Railway Information Systems) which was estabilished by the India's Ministry of Railways in 1986. It develops and manages most of the important information system of the Indian Railways.
www.irctc.co.in
IRCTC (Indian Railway Catering and Tourism Corporation) handles the catering, tourism and online ticketing operations. If you have booked tickets from their website you can login to IRCTC website and go to Booked Ticket History > E-Tickets > Get PNR Status.
How to check PNR status via SMS?
To check the status of PNR No. by SMS -

Type "PNR (10-digit PNR Number)" and send it to 139.
Type "PNR (10-digit PNR Number)" and send it to 5676747.
Example: PNR 4622661166
*Standard SMS charges would be applied.
Reliance Jio, Airtel, Vodafone, BSNL and all major telecom networks supported.

You may also download the IRCTC Rail Connect android app available on Google Play for seamless access to Bookings, Cancellation, Refuund History, TDR Filing, Meal Booking.
How to predict confirmation chances for a waitlisted ticket?
Whilst booking a ticket on the Indian Railway network, there is a pretty good chance that you will get a waitlisted ticket as it is pretty common. When all of the RAC seats are sold then the passengers are given Waiting List tickets.

If you are on the Waiting List then the chances of you getting a confirmed seat are if other passengers cancel their tickets. Ticket cancellations by other passengers will increase your chances of getting confirmed tickets.

What are types of Indian Railways Tickets?
E-Tickets: Electronic Tickets (E-Tickets) are ones which you receive on online booking. You can either show it through your mobile to Ticket Checker (TC) or you may print a physical copy before boarding the train.
i-Tickets: These are the tickets you get when booking directly from reservation counters. You may also book the same ticket from IRCTC website and get it delivered to your doorstep.
IRCTC handles over 500-600k daily bookings so chances of Tatkal booking confirmation is slim, you may want to read our what are confirmation chances for my waitlisted ticket? guide.

How to contact IRCTC?
Customer Care Numbers: 0755-6610661, 0755-4090600

If you have booked ticket through IRCTC:

I-tickets/e-tickets: [email protected]
For Cancellation E-tickets: [email protected]
You may also contact Indian Railways Seva on Twitter @RailwaySeva

Legends
Symbol Description
PNR Passenger Name Record
WL Waiting List
CNF / Confirmed Confirmed (Coach/Berth number)
RAC Reservation Against Cancellation
SL Sleeper Class
3A AC 3 Tier
3E AC 3 Tier Economy
2S Second Sitting
FC First Class
2A AC 2-Tier Sleeper
1A First Class AC
GN General Quota
DF Defence Quota
TQWL Tatkal Quota Waitlist
LD Ladies Quota
HP Physically Handicapped Quota