The military situation which became the 2nd Afghan War (1878-80) created the demand to urgently extend the railway towards the Afghan border. From Ruk a junction was created and the line forced northwards under Military supervision supplemented by engineers deployed from the Railway Branch of the Public Works Department(PWD).
1879 October 6th. First rail laid of the 20 mile section from Ruk to Sibi, at the entrance of the Nari Pass and this section was opened on 14th January 1880. The track of 133 miles had been laid in 101 days across the waterless desert by 5,000 men and their animals .
Reports of the time described this as the Sukkur-Dadur Railway:-
- General Stewart in a letter dated 6 October 1879 reports “they have started the Sukkur-Dadur Railway’
- “The New York Times” 11 Nov 1879 stated 'The Sukkur and Dadur Railway is open for engines nearly to Jacobabad, and is being constructed at the rate of over a mile per day’ 
- “The Times of London”, 17 Nov 1879 reported 'The Sukkur - Dadur Railway is now completed as far as Jacobabad and is - being rapidly pushed on towards Quetta. It is stated that the broad gauge will extend.....'.
See also Sind-Pishin State Railway but the following are specifically attributed to the 'Sukkur-Dadur Railway'
- “Administration Report on Railways 1918” page 98 (pdf107); Retrieved 20 Dec 2016 later known as the NWR ‘Kotri-Rohri (via Ruk) Branch Line’
- “Grace’s Guide “Sind-Pishkin Railway” ; Retrieved 20 Dec 2016
- My Heritage “Field Marshall Sir D Martin Stewart, 1824-1900”, Page 289(pdf363); Retrieved 20 Dec 2016
- “The New York Times” 11 Nov 1879; Retrieved 20 Dec 2016
- "The Times of London”, 17 Nov 1879; Retrieved 20 Dec 2016
- British Library - "Photographs Album details for shelfmark Photo 1085/9"; Retrieved 20 Dec 2016