Construction of railways and underground railways

SIC code 42120 is the UK Standard Industrial Classification (SIC 2007) for "Construction of railways and underground railways". It is the code a company records at Companies House when this is its business activity, and it sits within SIC section F — Construction.

2,867 companies are currently classified under SIC code 42120 on the UK register, most commonly in London, Birmingham, Sidcup.

On Company Shark, search the live Companies House register by SIC code 42120, then narrow by location and incorporation date and export the list with director details. SIC code filtering is available on the Business and MAX plans.

SIC codes are self-reported. Pick the code that most closely matches your main activity — 42120 covers "Construction of railways and underground railways". You can record up to four SIC codes, and update them on your annual confirmation statement.