To mark this improved channel, the Department of Marine rearranged the buoys it maintained along this section of the river and erected new range lights to equip the channel for night navigation. On October 27, 1903, three sets of range lights were established to guide mariners along the St. Lawrence River north of Contrecoeur and east of Île Saint-Ours: St. Ours Traverse Range, Petite Traverse Range, and Contrecoeur Course Range. (A new range was activated on July 15, 1904 to mark Contrecoeur Traverse.)
The front towers and rear towers used on the three ranges were similar. The front towers consisted of thirty-three-foot-tall, square, wooden, structures, with sloping sides and surmounted by a square lantern room, while the rear towers were square, steel, skeletal structures topped by an enclosed watchroom and a square, wooden lantern room. White slatwork was mounted on the side of the rear tower facing the range line for improved visibility during the day.
The following description of Petite Traverse Range was published shortly after the lights were placed in operation on October 27, 1903 to mark the axis of the cut in the improved ship channel known as Petite Traverse:
The lights and towers are similar in every respect to those last described, marking the St. Ours traverse.Bellmouth Curve is located of the eastern side of Île St. Ours, while Contrecoeur Bend is located west of the northern end of the Contrecoeur Islands.
The front tower stands on the ground on the crest of the river bank east of St. Ours traverse, 185 feet from the position occupied by the day beacon which it replaces, and 6735 feet N. 27° 24’ E. from St. Ours traverse front range lighthouse.
The light is elevated 62 feet above the level of the river.
The back tower stands in the fields 205 feet N. from the day beacon which it replaces, and 1830 feet N. 61° E. from the front tower. The light is elevated 117 feet above the level of the river.
The two lights in one astern lead through Petite Traverse in the axis of the ship channel, from Bellmouth curve to Contrecoeur bend.
Louis Caisse was hired as the first keeper of Petite Traverse Front Range Light at an annual salary of $100, while Ed. St. Laurent received the same amount to look after the companion rear light.
Petite Traverse Range remains active today, displaying fixed green lights from a cylindrical tower at the front location and from a square, skeleton tower at the rear location.