Among his achievements was the building of numerous roads that linked various towns. He also enabled much progress in the construction of the East Indian Railway. Both of these were seen by Halliday as necessities, for he recognised that speedy and accurate communication was a prerequisite for efficient administration. He introduced the Calcutta Municipal Act, enacted reforms of the police service (including better pay), tightened supervision of the inefficient justice system and increased the number of its officials. Arrangements were also introduced to limit civil disturbances and disruption by, for example, creating a force of military police. Although Bengal was on the periphery of events relating to the Indian rebellion of 1857, and Halliday was commended for his successes in dealing with civil unrest, he provided advice to Lord Canning, the governor-general, regarding how to deal with the rebellion elsewhere. He had past experience of uprisings, including one that had occurred at Santal in 1855, soon after his appointment to office.