Below are given seven sentences out of which the sentence numbered 5 has been correctly placed and is fixed. The rest of the sentences A, B, C, D, E, F needs to be arranged correctly in order to form a logical order. Keep in mind that there are a total of seven sentences with the 5th sentence already given. 

A. It manages the fourth largest railway network in the world by size, with a route length of 67,368 kilometres and total track length of 121,407 kilometres.

B. It is also the world's eighth-largest employer with 1.308 million employees as of March 2017.

C. In the freight segment, IR runs more than 9,200 trains daily.

D. The average speed of freight trains is around 24 kilometres per hour.

5. Mail or express trains, the most common types, run at an average speed of 50.6 kilometres per hour. 

E. Indian Railway (IR) runs more than 20,000 passenger trains daily, on both long-distance and suburban routes, from 7,349 stations across India.

F. Indian Railways (IR) is India's national railway system operated by the Ministry of Railways.