Boston Lodge works, established circa 1808 as the quarry and workshop site for the construction of the Cob causeway, is the world oldest railway works. Uniquely having constructed steam locomotives in the 19th, 20th and 21st centuries Boston Lodge remains the principal engineering works for the Festiniog and Welsh Highland railways. The highly capable team at the works today continue to overhaul and construct new locomotives and coaches, including constructing replica rolling stock for several other narrow gauge heritage railways.
Like all workshop sites with long histories there have been many alterations, additions and changes to the site over the course of 200 years, with early structures built from the stone quarried on site to the use of corrugated iron in the mid-20th century. Many of the buildings are quite typical of their construction period, so can easily be fitted into other settings to replicate the similar choices of building materials from different eras.