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ADJ. 
3985 specifications
The American Standard 3985 is a sophisticated locomotive design that reflects the pinnacle of steam technology in the mid-20th century. Built for the Southern Pacific Railroad, the 3985 is a "4000" series locomotive, recognized for its impressive engineering and efficiency. This locomotive is particularly notable for its large size and power, making it one of the largest steam locomotives ever constructed.One of the standout features of the 3985 is its massive driving wheels, which measure a substantial 69 inches in diameter. This size not only provides greater traction but also allows for better stability while traveling at high speeds. The locomotive is equipped with a 4-8-8-4 wheel arrangement, signifying its four leading wheels, four driving wheels on the front set, and a unique four driving wheels on the rear set. This configuration enhances its load-hauling capability and contributes to its impressive performance on various rail gradients.
The American Standard 3985 employs innovative technologies for its time, including a modernized firebox and an efficient superheater system. The superheater increases steam temperature before it enters the cylinders, enabling greater engine efficiency and performance. Moreover, the locomotive features a large smokebox that improves airflow and reduces soot buildup, thereby allowing for longer operational periods between maintenance.
Another key characteristic of the 3985 is its spacious cabin, which provides ample room for the crew to navigate during long journeys. This thoughtful design enhances safety and comfort, as operations can be efficiently managed even during extended runs. The incorporated sound-dampening materials improve the working conditions for the crew, allowing them to communicate more effectively.
The American Standard 3985 is not just a marvel of engineering but also a symbol of the steam era's grand legacy. It has undergone several restorations to ensure its safety and functionality, preserving it for future generations to admire. The locomotive’s historical significance and engineering achievements make it a cherished piece of American railway heritage, representing the ambition and innovation of its time. As it continues to operate on special occasions, the 3985 stands as a testament to the enduring power and beauty of steam locomotion.