By 1916, the Detective and Police work of the Caledonian Railway had been growing in importance. Each department had dealt with its own particular cases up to that time. The Directors of the Caledonian Company decided that, from 1 January 1917, the Police and Detective staffs of the various departments would be amalgamated.

Mr Alexander Lang was selected to take charge of the new consolidated force that would cover the whole of the Caledonian system from Aberdeen to Carlisle. Mr Lang was to be headquartered in Glasgow and to be known as the Chief of Police.

Mr Lang had for many years previous acted as Detective Inspector of the passenger department. He was a native of New Stevenston, Holytown, and entered the services of the Railway in 1888 as a bookmarker in a signal box at Mossend. After serving as a telegraph boy in signal boxes in that district, he was appointed a year later to act as boy porter at Holytown, and for the next six or seven years served at various stations in different capacities. In 1894, he was promoted to the post of ticket collector at Holytown where he remained for two years.

It was while at Holytown station that the new Chief of Police showed signs of his Detective ability in several cases which he handled in a tactical and successful manner. As the result he was in 1897 appointed Assistant Detective at Glasgow, and in 1907, he was given charge of the Detective Department. Since that time, his abilities were repeatedly recognised by the officers of the company. His duties brought him in contact with all ranks and classes, and his success in organisation and in tracking criminals won him very high compliments.