First, Link and Pin are drawbars, not couplers... Couplers (per MC
are automatic devices which can be coupled or uncoupled without going between cars...
The D&RG (no W yet) purchased a large number of cars, including the 3000 class box cars, the short stock cars and reffers, and the drop bottom gons in 1903, all equipped with air brakes and vertical plane (aka knuckle or Janey) couplers mostly ending the use of link and pin... SAM safety link and pin couplers were used for a few years longer... they were automatic if coupled to another SAM... The SPng got sued after a trainman was injured when coupling two dissimilar cars ending the belief that SAM or Miller couplers were acceptable options with knuckle couplers.
There is a lot of literature suggesting that links migrated... crews horded a supply of links and pins... since the draw heads had different size holes, and had different size throats and draw bar height was not yet standard, some links would not work with some draw bars, some pins wouldn't work with some draw bars, and crooked links were used to allow for height differences... A crew with a good assortment could make up a train that a lesser or less prepared crew would fight with...
Randy