Question: How long is one of the races the horse Rock Fall won?

Context paragraphs:
Edwards v National Coal Board: Edwards v. National Coal Board was an important case in English case law.  The 1949 case revolved around whether it was "reasonably practicable" to prevent even the smallest possibility of a rock fall in a coal mine.

Horse Rock Ridge: Horse Rock Ridge is a ridgetop located on the western edge of the Cascade Range near Crawfordsville, Oregon.  The site is recognized for its considerable diversity of plant species that includes both Willamette Valley plants as well as plants more often found in the mountain zone of the Cascade Range.  There are also several plant species more often found east of the Cascade Range.

Group races: Group races, also known as Pattern races, or Graded races in some jurisdictions, are the highest level of races in Thoroughbred horse racing.  They include most of the world's iconic races, such as, in Europe, the Epsom Derby, Irish Derby and Prix de l'Arc de Triomphe, in Australia, the Melbourne Cup and in the United States, the Kentucky Derby and Breeders' Cup races.  Victory in these races marks a horse as being particularly talented, if not exceptional, and they are extremely important in determining stud values.  They are also sometimes referred to as Black type races, since any horse that has won one of these races is printed in bold type in sales catalogues.

Alfred G. Vanderbilt Handicap: The Alfred G. Vanderbilt Handicap is an American Thoroughbred horse race held annually near the end of July at Saratoga Race Course in Saratoga Springs, New York.  A Grade I event open to horses age three and older, it is a six furlong sprint raced on dirt.

Claiming race: A claiming race in thoroughbred horse racing is one in which the horses are all for sale for more or less the same price (the "claiming price") up until shortly before the race.  Race types form a hierarchy in terms of the quality of horse they attract, with handicap races and graded stakes races attracting the "best" horses and maiden races the most unseasoned.  Claiming races fall at the bottom of this hierarchy, below maiden races, and make up the bulk of races run at most US tracks.  For example in Kentucky in 1999, 54% of all races run were claiming races, but had only 20% of the purse dollar value, the lowest average purse among race types.

Pantai Remis landslide: The Pantai Remis landslide was a rock fall and flood that occurred on 21 October 1993, near Pantai Remis in Perak, Malaysia.  The landslide took place in an abandoned open cast tin mine close to the coast.  This area of Malaysia is well known for its tin mining industry.  Video footage shows the rapid collapse of the working face closest the sea, allowing complete flooding of the mine and forming a new cove measuring approximately 0.5 km2 .

Puerto Rico Highway 167: Puerto Rico Highway 167 is one of the main highways in the San Juan–Caguas–Guaynabo metropolitan area of Puerto Rico.  This Highway starts at Puerto Rico Highway 165 in Levittown and goes until Puerto Rico Highway 156 in Comerío.  It is two-lane per direction all through Cataño and a vast area of Bayamón, and becomes rural a couple of kilometers before entering through Naranjito.  During the rainy season this road is risky as there is chance of rock fall and debris onto the road.  This happens mainly due to increase in moisture content in the soil, which loosens the suspending rocks adjacent to the highway.  It is proposed to make this road fully parallel to the future tollway PR-5, which will be extended until Comerío.  The future tollway will pass through the only cable-suspended bridge in the island in Bayamón near the border with Naranjito.

Axenstrasse: The Axenstrasse is an 11.4 km two-lane middle section with ongoing traffic between the A4 motorway and the A2 motorway, and part of European route E41 between the resort of Brunnen in the canton of Schwyz to the village of Flüelen in the canton of Uri in Central Switzerland.  The road is built along steep cliffs on the east side of the Urnersee (first part of the Lake Lucerne) weaving through many rock fall galleries and tunnels along its route.  Upon completion in 1865, the Axenstrasse was the first way to get to Uri that did not involve navigating Lake Lucerne.

Rock Fall (horse): Rock Fall (foaled March 19, 2011 – October 10, 2014) is a racehorse best known for winning Alfred G. Vanderbilt Handicap, and the Vosburgh Stakes

Weight for Age: Weight for Age (WFA) is a term in Thoroughbred horse racing which is one of the conditions for a race.  It means that a horse will carry a set weight in accordance with the Weight for Age Scale.  This weight varies depending on the horse’s age, its sex, the race distance and the month of the year.  Weight for age races are usually Group 1 races, races of the highest quality.  It is a form of handicapping for horse racing, but within the horse racing industry is not referred to as handicap which is reserved for more general handicapping.

Supporting paragraphs: Rock Fall (horse) Alfred G. Vanderbilt Handicap
Answer: six furlong sprint