| Overview | |
|---|---|
| Franchise(s): | North London Railways 2 March 1997 – 10 November 2007 |
| Main region(s): | Greater London |
| Other region(s): |
Bedfordshire, Buckinghamshire, Hertfordshire, Northamptonshire |
| Fleet size: | 67 |
| Stations called at: | 88 |
| National Rail abbreviation: | SS |
| Parent company: | National Express Group |