The Blue Mountain Quarry is situated on the Skarloey Railway, and is 1 of Sodor's largest blasting operations. Owen, Wendy and Merrick reside here, as well as several of the Narrow Gauge Engines and workmen.
The quarry is a large operation, with massive terraces and pieces of construction equipment. Some of the most notable features of the quarry include:
- Blondin Bridge
- Owen the Incline
- Merrick the Crane
- Steam-Powered Hammer
- A Conveyer Belt
- A zipline
- Wendy the Winchouse
- A turntable
Later, Thomas was sent to work there and was amazed by the scope of the quarry. He talked to several of his Narrow Gauge friends and met Merrick and Owen before meeting Luke, a small engine who was afraid of being sent away due to his knocking Victor into the sea. Thomas managed to persuade Luke to come out of hiding, and, after a series of events involving Diesel and Owen, Luke now works happily with his Narrow Gauge friends at the quarry.
Mille had an accident with Wendy the Winchouse on the same day that Sir Robert Norramby found King Orry's Sword here with the help of Luke and Millie.
- Foreman Okamoto
- Scott Wallis
- Several Workers
- The Pack (occasionally)
- Season 1: Double Whammy, Greg and Lars
- Season 2: Paxton and Norman (mentioned), Two Hearts Burn Together (mentioned), Blunderbuss, Swan Dive, Luke and Millie's Blue Mountain Adventure, All the World's a Stage, Swashbuckler
- Season 3: Chivalry is Dead, Merrick's Wake up Call