| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| Mtr Laing Railway Co Ltd | 05336720 | 19/01/2005 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| ARRIVA TRAINS HOLDINGS LIMITED | 03076782 | 11/07/2002 | 18/12/2015 | Gold |
| AYLESBURY VALE PARKWAY LIMITED | 05840872 | 08/06/2006 | 25/01/2008 | Silver |
| CHRISTIAN ENGINEERS IN DEVELOPMENT | 01980353 | 26/06/2010 | 20/06/2015 | Gold |
| JOHN LAING PROJECTS & DEVELOPMENTS (HOLDINGS) LIMITED | 04252518 | 10/01/2007 | 26/07/2007 | Gold |
| JOHN LAING PROJECTS & DEVELOPMENTS LIMITED | 04420886 | 14/01/2003 | 26/07/2007 | Bronze |
| LONDON AND NORTH WESTERN RAILWAY COMPANY LIMITED | 02880012 | 01/06/2014 | 18/12/2015 | Gold |
| M40 TRAINS LIMITED | 03005018 | 27/07/2006 | 18/12/2015 | Gold |
| THE CHILTERN RAILWAY COMPANY LIMITED | 03007939 | 16/05/2011 | 18/12/2015 | Silver |
| WSMR (HOLDINGS) LIMITED | 05970324 | 18/10/2006 | 31/03/2008 | Not Trading |