High Track was a 3.94 mile section of the Canadian Northern Railway mainline that ran between Stanley and Kakabeka. When constructed, the CNoR line to Winnipeg used the original PAD&W grade from Port Arthur to Stanley (MP 19) before turning and climbing northwest to Kakabeka and beyond. However, the company realized very quickly that this section of the line was not ideal to due the heavy grades and some tight turns. There were numerous accidents involving heavily-laden trains coming downhill into Stanley.
In 1909, Canadian Northern decided to remedy the problem by building a new section of grade from Twin City to Kakabeka. Completed in 1911, the new line not only reduced the incline trains had to negiotate, but it was also 1.5 miles shorter than the original route. High Track was abandoned and the track between Twin City and Stanley was now relegated to branch line status along with the west of the old PAD&W (known as the CNoR-North Lake Branch).
Link to 1928 map.
There are a number of videos of High Track and the area around it in the playlist below.