Theory:

     ‘But the papers announced the opening of the railway throughout.’
 
     ‘What can I tell you, officer? The papers were mistaken.’
 
     ‘Yet you sell tickets from Bombay to Calcutta,’ snapped Sir Francis, who was growing angry.

     ‘No doubt,’ replied the conductor; ‘but the passengers know that they must provide means of transportation for themselves from Kholby to Allahabad.’
 
     Sir Francis was furious. Passepartout would willingly have knocked the conductor down, and did not dare to look at Mr.Fogg.
Explanation:
 
Still, Francis was confused. He was irritated with the conductor's answer. He claimed to have read in the papers about the opening of the railway throughout. So, the rail route must have been connected from Bombay to Calcutta was Sir Francis's argument.

The conductor had understood the reason behind Mr. Francis' argument. The fact behind this was that, since it was mentioned on papers that the railroad connects throughout, Mr. Fogg and his team opted to complete their journey using train from Bombay to Calcutta. Since all three are from other countries, they were not aware that the railway built from Kholby to Allahabad was in progress. They missed to add those details in the papers that people had to use some other means of transport for those fifty kilometres (from Kholby to Allahabad).

The conductor, having understood the issue, explained these details to Mr. Francis. Francis was even angrier to hear this reply from the conductor; he asked the conductor why they sell tickets from Bombay to Calcutta, despite having no rail route for those fifty kilometres. The conductor informed them that the passengers were already aware of availing themselves transport for the fifty kilometres.
 
shutterstock_1600351033 (1).jpg
Train conductor

Sir Francis was angry. Passepartout did not dare to even look at Mr. Fogg. He wished to hit the conductor hard for his awful explanation on train destination at Kholby.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Furious
Extremely angry
2.
Throughout
From the beginning to the end
3.
Snap
A sudden sharp noise
4.
Knock
To hit somebody or someone hard
5.
DareTo have enough courage to try or do something  
Reference:
State Council of Educational Research and Training (2019). Term-3 English Standard-7. A Journey by Train by Jules Verne (pp. 79-85). Published by the Tamil Nadu Textbook and Educational Services Corporation.