These "Brandt" movements were made from 1905 approximately. Bill Sohne says that they were labeled "Louis Brandt" to get around Omega Dealer agreements, because dealers selling railroad watches wer different from those that would sell Omega watches in the same country... But you have to remember that "Omega" initially was the name of the 19"' caliber made by Louis Brandt & Frères. It is only later (between 1903-1905...) that the company took the name of Omega. The calibers were exported uncased, and cased in the country where they were sold.
There were many grades (A, B, C, CC, CCR, CCCR, DR, DDR...) and the fully jewelled and gold-set ("chatons") grades CCR and CCCR were called "Canadian" calibers. This is because most of them were exported to Canada to be used in Railroad chronometers. The Canadian Pacific Railways was the only North American railway company that accepted Swiss movements in their chronometers... Mostly US watch companies provided these official timepieces: Elgin, Illinois, and of course, Waltham.
More information: here and there.
From the Omega website:
Official Watch of the Canadian RailwaysI took these pictures of my CPR chronometer tonight:
The company first supplied the Canadian Railways in 1905 with a "Ls Brandt & Frère SA - Grade CCR" branded pocket watch with a 20"' calibre. Representing the best quality of the time, the watch was water resistant and had a dustproof band at the pendant to protect the movement from dust and humidity. The movement itself was CCR quality, reserved at the time for 19 and 20"' high-precision finely finished official chronometers: it had 19 jewels including 10 with collets; rubies set into screwed gold collets, gold balance screws, jewel-set barrel, index with screw or with graduated index-snail, double steel plate, Breguet balance, pallets and spring of superior quality, barrel stop for large pieces, precision adjustment in five positions and temperatures for a rate deviation of less than one minute per week, with rate certificate on request.
A new Ls Brandt branded watch and one OMEGA were produced for the Canadian Railways in 1906 and later a Brandt-OMEGA in 1910, a Ls Brandt in 1911 and a watch for the Watch Inspector in 1915.