From Rajmahal, EIR’s lines proceeded westwards along the Ganges rapidly, reaching Bhagalpur in 1861, Monghyr (Munger) in February 1862 and opposite Benares in December 1862. This included EIR’s first tunnel at Jamalpur and the first major bridge on the route, over the Sone at Arrah.
Benaras was connected to Mirzapur on 1st January 1864, and to Allahabad by April 1862. Simultaneously, the Allahabad-Kanpur-Tundla line was also completed.
The earlier idea of crossing the Jamuna at Agra and proceed to Delhi was given up in favour of routing the line via Ghaziabad.
Tundla-Aligarh line was opened in March 1863 and Aligarh-Ghaziabad in April 1864.
Meanwhile the Government decided to change the route to Lahore via Meerut and Saharanpur instead of via Delhi and Ferozpur.
The bridge over the Jamuna near Delhi was constructed nevertheless, as the materials for the bridge had arrived from England.
Ghaziabad was the junction of the EIR with Delhi and Lahore Railway.
The bridge on the Jamuna at Naini, near Allahabad, was opened in August 1865, to provide a through line from Calcutta to Agra. Thus the landmark of joining the two great rivers i.e. from the right bank of Hooghly at Calcutta to the left bank of Jamuna at Agra – a stretch of 1,017 miles was accomplished.
With the opening of the Jamuna bridge at Delhi in 1866, the last link of the trunk line between Calcutta and Delhi was completed.
The Allahabad-Jubbulpore line was opened in June 1867, furnishing a link with the GIP Railway, and making it possible to travel directly from Calcutta to Bombay.
The route was officially opened on 7th March 1870, in a spectacular ceremony performed by the Viceroy, Lord Mayo with His Highness, the Duke of Edinburgh as chief guest. Lord Mayo concluded “it was thought desirable that, if possible, at the earliest possible moment, the whole country should be covered with a network of lines in a uniform system”.