SIC code 42120
Construction of railways and underground railways
There are about 2,580 active UK companies registered under SIC code 42120 (Construction of railways and underground railways), as of October 2026.
Live figures, the full list, more filters, and CSV export.
On the register
Share of these companies on the live register, by status.
- Active 58%
- Proposal to strike off 40%
- In insolvency or administration 2%
New registrations
Companies registered each month, October 2025 – September 2026, that are still on the register. See registrations by month across all companies.
Show the figures
| Month | Companies |
|---|---|
| October 2025 | 33 |
| November 2025 | 24 |
| December 2025 | 18 |
| January 2026 | 28 |
| February 2026 | 11 |
| March 2026 | 22 |
| April 2026 | 17 |
| May 2026 | 20 |
| June 2026 | 24 |
| July 2026 | 22 |
| August 2026 | 20 |
| September 2026 | 18 |
Company age
How long the active companies have been registered.
- Under 1 year 10%
- 1–3 years 17%
- 3–5 years 14%
- 5–10 years 30%
- 10–20 years 26%
- 20 years or more 3%
Where they're registered
Active companies by postcode area of their registered office.
- South East London (SE) 136
- Romford (RM) 127
- East London (E) 122
- Dartford (DA) 113
- Cardiff (CF) 85
- Harrow (HA) 73
- Ilford (IG) 69
- North London (N) 65
- Canterbury (CT) 61
- West London (W) 61
Note: Location figures use the registered office address from Companies House. Many companies register at an accountant's or formation agent's address, which may differ from where they trade.
Recently registered companies
Active companies recently registered under SIC code 42120.
| Company | Number | Registered | Town |
|---|---|---|---|
| L T CONSTRUCTION SERVICES LIMITED | 17491457 | 30 Sept 2026 | WETHERBY |
| RAIL BASED CONTRACTING SERVICES LTD | 17485603 | 28 Sept 2026 | CREWE |
| ADD22 LTD | 17477876 | 23 Sept 2026 | HARROW |
| AH RAIL AND CIVILS LIMITED | 17476918 | 23 Sept 2026 | BRIGHTON |
| FRESH RAIL LTD | 17474209 | 22 Sept 2026 | FAVERSHAM |
| RB RAIL LIMITED | 17472145 | 21 Sept 2026 | WORKSOP |
| PORTAL RAILWAY SERVICES LTD | SC902914 | 16 Sept 2026 | MOTHERWELL |
| LEE.T73 RAIL LTD | 17459670 | 15 Sept 2026 | SWANSEA |
| FLYNN RAIL SERVICES LTD | 17454272 | 11 Sept 2026 | LONDON |
| ECS ISREAL LTD | 17452354 | 11 Sept 2026 | SANDBACH |
Related
- Part of the Construction industry group.
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Other construction SIC codes:
- 41100 – Development of building projects (109,000)
- 41202 – Construction of domestic buildings (92,800)
- 43999 – Other specialised construction activities n.e.c. (61,900)
- 43210 – Electrical installation (56,100)
- 43390 – Other building completion and finishing (54,900)
- 43220 – Plumbing, heat and air-conditioning installation (49,800)
- 41201 – Construction of commercial buildings (39,900)
- 43290 – Other construction installation (37,200)
- All SIC codes
- SIC codes explained
- New Company Registrations
- New / Updated Officers
- Charges / Mortgages
- Officer Disqualifications
- Accounts (Assets)
- Insolvency Filings
- Company Officer Resignations
- Existing Company Changes
- In Liquidation
Data as of .