UK SIC 2007 code in Section F: Construction
42120 Construction of railways and underground railways
SIC 42120 is the UK code for construction of railways and underground railways. Companies House accepts it when you register a company or file a confirmation statement.
- Code
- 42120 (UK SIC 2007, Companies House list)
- Section
- Section F: Construction
- Division
- 42 Civil engineering
- SIC 2026
- 42.12 Construction of railways and underground railways (1:1)
- Closest US NAICS
- 238990
Activities ONS lists under 42120
The ONS index assigns these 9 activities to this code. If one describes your company, this is the code to use.
- Cable supported transport systems construction
- Construction of underground railways
- Railway construction
- Railway tunnel construction
- Railway tunnelling contractor
- Subway construction
- Supply line (third rail) for railway construction
- Tramways construction
- Transmission line construction
Source: ONS UK SIC 2007 alphabetical index.
What changes in SIC 2026
ONS published UK SIC 2026 in 2026. Its correspondence table maps this code's class (42.12) to:
| SIC 2026 code | Heading | Link type |
|---|---|---|
| 42.12 | Construction of railways and underground railways | 1:1 |
"1:1" means the class carries over unchanged in scope; other link types mean it was split or merged. Companies House still uses SIC 2007, so keep filing with 42120 until it announces a switch.
Closest US NAICS codes
Matched through the shared international class (ISIC Rev. 4). Treat these as a starting point and read the definition before using one.
Similar codes to compare
Data last changed November 14, 2026. Source: Companies House condensed SIC list. How this page is built.