S4 57,58,60 CNF

I am going to write about an incident that happened many years ago. Yes,it does involve a train journey.
We had gone to kerala to attend my grandmom's 80th bday celebs.After the celebrations , we got ready(my father,mother and me) for the journey back home. My mother, tensed as she is everytime before a journey made us reach the railway station an hour early before the actual arrival of the train. We sat at the station just talking about the day and having some quality family time.Now, we were waiting for the 9.00 PM Alleppey train to arrive. And we were there by 8 itself. So we had a lot of time to chit chat. Though we had around 1 hour with us, we didn't give the ticket a second look.
By 8.45 , Chennai Mail came and left. With its departure, we got up and walked to the coach of the train before it arrived. The coach was S4 and the seats were 57,58,60 CNF. When the train arrived, we got in and located our seats. In our seats were an elderly couple. We dedided to let them know of the ownership of the seats they were sitting in after we finshed our dinner. We slowly had our dinner and we let them know of our intention to sleep where they were sitting. That's when they told us that the seats belonged to them. My father quickly took out the ticket and verified again. It was the same number as them. We both had identical tickets. Then we checked the dates. The date too was correct.Since. their ticket was already verified by the TTE, my father went searching for him.
My father found him and told him the problem. The TTE looked at our ticket and then looked at my father and said "You can pay a fine and then travel". My father was taken aback. He asked why should we pay the fine.It is the mistake of the railway reservation system.The TTE pointed to the train name to my father. He then realised that we had taken the wromg train!!!! We were supposed to board the 8.45 Chennai MAil and not the 9.00 PM Allppey Express. Not knowing what to do, my father asked for our next step. We weren't ready to go to the general compartent.So we ended up doing a favour to the TTE and he aranged three berths for us ovrenight. We apologised to the elderly couple and slept thnking what a fool we had made of ourselves.
You might be thinking that this might have been one of our first journeys by train, We had been travelling on the train for 25 years before this incident and this had never happened to any one of us. And this didn happen many years ago. It happened just two weeks back. I didn want u guys thinking how careless we were until the end of this post...
I don't understand how on earth we boarded the wrong train. Anyways we learnt our lesson that day.