Ånglok

Ånglok is the Swedish term for a steam locomotive. A steam locomotive is a railway locomotive powered by a steam engine. Steam is produced in a boiler by burning fuel such as coal or oil. The steam's high pressure pushes pistons in cylinders; the pistons drive the locomotive's wheels through connecting rods and a system of gears. Most steam locomotives use a valve gear to control steam admission and release, with common designs including Stephenson or Walschaerts gear. Locomotives can have two or more cylinders, and wheel arrangements are described by the Whyte notation, indicating the number of leading, driving, and trailing wheels. A separate tender often carries fuel and water.

Usage and development: From the early days of railways, Ånglok were the dominant motive power for freight and passenger services. They enabled heavier loads and longer distances than earlier locomotives and spurred rapid railway expansion worldwide. In the mid-20th century, diesel and electric traction gradually replaced steam locomotives in most countries, due to lower operating costs and simpler maintenance. Some remained in service longer in remote regions or on heritage networks.

Preservation: Today, many Ånglok are preserved in museums or operate on heritage railways. They are valued for historical and engineering significance, illustrating the technology and working life of the steam era. In Sweden and elsewhere, surviving examples are maintained by museums, railways, and enthusiast groups, preserving the industrial heritage of steam propulsion.