There are 2,171 active companies in the construction of railways and underground railways sector in the UK (SIC code 42120). This sector falls under Section F — Construction — of the UK Standard Industrial Classification. The sector has a relatively low 15.3% dissolution rate — 2,171 of 4,009 registrations remain active. Recent formation activity is notable, with 67.8% of current companies established in the 2020s. 177% of companies were formed after 2010, marking this as a sector with predominantly recent entrants. The average company age in this sector is 7.1 years. London leads with 24% of companies in this sector. Companies in this sector hold 142 government contracts valued at £1.6B.
Source: Companies House register via UVAGATRON, October 2026
A rapidly growing sector with 67.8% of active companies formed since 2020.
The construction of railways and underground railways sector has a <Link href="/glossary/company-dissolution">15.3% dissolution rate</Link>. The average active company in this sector is 7.1 years old. Geographic concentration: 24% in LONDON.
Companies in the construction of railways and underground railways sector have been awarded 142 government contracts worth £1586.6M in total.
There are 2,171 active companies classified under SIC code 42120 (Construction of railways and underground railways) in the UK, out of 4,009 total registered.
SIC code 42120 stands for "Construction of railways and underground railways". It belongs to Section F — Construction of the UK Standard Industrial Classification.
The largest concentrations are in LONDON (527), SIDCUP (41), DONCASTER (39).
The average active construction of railways and underground railways company in the UK is 7.1 years old, with the oldest registration dating back to 1930.
Our database contains 18,462 data signals across 11 categories for active construction of railways and underground railways companies. The largest category is Governance with 8,992 signals from 5 government sources.
5.9M companies, 50M+ signals from 53 government sources. Risk scores, director networks, entity analysis.