There are 2,262 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 8.9% dissolution rate — 2,262 of 3,989 registrations remain active. Recent formation activity is notable, with 66.7% of current companies established in the 2020s. 169% of companies were formed after 2010, marking this as a sector with predominantly recent entrants. The average company age in this sector is 6.9 years. London leads with 23% of companies in this sector. Companies in this sector hold 137 government contracts valued at £1.6B.
Source: Companies House register via UVAGATRON, September 2026
A rapidly growing sector with 66.7% of active companies formed since 2020.
The construction of railways and underground railways sector has a <Link href="/glossary/company-dissolution">8.9% dissolution rate</Link>. The average active company in this sector is 6.9 years old. Geographic concentration: 23% in LONDON.
Companies in the construction of railways and underground railways sector have been awarded 137 government contracts worth £1585.4M in total.
There are 2,262 active companies classified under SIC code 42120 (Construction of railways and underground railways) in the UK, out of 3,989 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 6.9 years old, with the oldest registration dating back to 1930.
Our database contains 13,865 data signals across 11 categories for active construction of railways and underground railways companies. The largest category is Governance with 6,947 signals from 6 government sources.
5.9M companies, 50M+ signals from 53 government sources. Risk scores, director networks, entity analysis.