I will tell you one interesting trick which I discovered to AVOID booking Tatkal.
It's by no means, foolproof, and it's very likely that I got lucky. But the math seems to make sense. Don't hold me responsible if it doesn't work.
See the coach layout of your train and decide which class you want to book. See the number of seats in the said family of coach.
Now, go to indianrail website (not irctc), check availability 120 days from today by inputting the train number, source & destination.
Make a note of how many seats it shows available.
Now do the same for your required journey date and see what is the WL count and TYPE (RL/PQ/GN).
The chance of ticket confirmation priority is: (head office/defence quotas) > GNWL > RLWL > PQWL > everything else.
Head office & defence quotas are usually very small in number to make any significance.
- If your required-date availability enquiry is showing as RLWL, then change the source station to somewhere near the starting station of the train (may have to adjust the journey date accordingly). Keep doing this until you get GNWL.
- Once you arrive at a station which is giving you GNWL number, do some math as given below:
- Total number of berths = berth per coach * number of coaches (A)
- Berths that were confirmed-booked = number seen as available 120 days in advance for the same pair of source-destination. (B)
- Effective number of berths which have been pushed under WL = (A) - (B) [C]
- WL will typically have two numbers, which says WL X/Y - where X is the max number, and Y is the current number (or the number you will get when you book).
- If the number Y is <= number obtained in Step 2 [C], you can take a risk & book the WL ticket, your ticket will most likely get confirmed at the time of charting. If you wish, you can consider some margin of safety in this.
I did this study on a few trains and discovered roughly 30% seats are only released for confirmed-booked status. Everything else is pushed by railways under WL, I don't know the reason behind this.
For highest possible chances - book GNWL only - it may even mean paying a bit higher fare compared to normal, but when you do that, mark the "boarding at" your station. It's very likely cheaper in comparison to Tatkal & Premium Tatkal though.
RLWLs also get confirmed, but it's a gimmick. GNWL has highest priority since AFAIK it is allocated only to full length passengers.
Based on the above math, I recently made a relative book WL 25,26 in a train having just ONE 2A coach. 2 hours before the charting time, the WL count went down to 15,16 and few minutes before charting, it was WL 8,9 and then it was confirmed.
Although for booking GNWL, the relative had to book a signifnicantly longer journey 1798 km journey vs 1048 km. Fare difference of ₹790.
Different charting time - the chart was prepared previous day at the origin station and relative boarded next day afternoon at their station which falls en route.
The extra fare difference was probably more than Tatkal, but at least significantly less uncertainty and headache compared to Tatkal.
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That said, the best way to have certainty while booking Tatkal is to use a payment provider which doesn't require OTP - HDFC Credit/Debit cards can be authenticated with a static password, or you can take Axis Bank OneTouch Token (this I have used for Tatkal booking).
The milliseconds delay in payment processing is the game changer. OTP is usually the delay because too many parties involved in it (IRCTC, Bank, Telco, etc).
