Theory:

     “Look Merlin, can you see that bird there? It is such a pretty blue and has such a lovely crown,” she said. Just then the train stopped suddenly with a thud.
 
     “Oh, what happened?” asked a boy. “Hey, why has the train stopped?” shouted another passenger.
 
     But, nothing could stop Muthu. He and his friends were the first to step out to see what had happened. Geetha madam tried to stop the children running out but they were too excited and begged to be allowed to go out. In the end the whole compartment stepped out. And what a sight greeted their eyes!
Explanation:
  
Fatima saw a pretty blue coloured bird with a beautiful crown; it could have been a peacock. Just then the train stopped with a sudden heavy sound. One of the boys asked what happened, while another passenger shouted why the train had stopped.
 
Nobody could stop Muthu, as he and his friends stepped out of the train to see what happened. Geetha madam could not stop the kids as they were too excited and begged for permission to step out. The whole compartment was out in some time. They all saw a beautiful sight.
 
people out of toy train.jpg
*Slowly all the people in the compartment stepped out!
 
Meanings of difficult words:
  
No.
Words
Meanings
1
thuda dull, heavy sound made by an object falling on the ground
Reference:
*Image courtesy - https://upload.wikimedia.org/wikipedia/commons/thumb/a/a9/Nilgiri_Mountain_Railways%2C_Hillgrove_Station%2C_India.jpg/1280px-Nilgiri_Mountain_Railways%2C_Hillgrove_Station%2C_India.jpg.
 
State Council of Educational Research and Training (2019). Term-2 English Standard-6. Trip to Ooty(pp. 111-127). Published by the Tamil Nadu Textbook and Educational Services Corporation.