Despite being enshrined in the BNA Act of 1867, it would still be another decade before a route was finally selected and construction was completed; however, as a start, the federal government assumed the operations of the NSR and E&NA which were to be wholly absorbed into the ICR. The route connecting the NSR and the E&NA was not contestable as the line had to cross the Cobequid Mountains and the Isthmus of Chignecto where options were limited by the local topography. In New Brunswick, it was a different story, as the choice was narrowed to three options. A commission of engineers, headed by Sir Sandford Fleming had been unanimously appointed in 1863 to consider the following: