Erected in 1836 as part of Boston Lodge Railway Works (nprn 91422), the four-bay iron foundry is built of local slatey rubble, under a corrugated iron roof with wide eaves. It has large, voussoir-arched openings on the west side; three are blocked-up but the north one retains a boarded door. On the east side are lateral chimneys and segmental arches into deep lean-to chambers. The interior retains deep brackets in one wall indicating the position of the cupola hood.
RCAHMW, 05 June 2008.