A (S-train)
A is a service on the S-train network in Copenhagen. It is one of the base services on the network, running every 20 minutes from about 5:00 to 0:30 every day, and every 10 minutes from about 6:15 to 19:00. It runs between Hundige and Hillerød, serving all stations on the inner part of the Køge radial. During daytime on weekdays, every second train continues from Hundige station to Solrød Strand station. On Friday and Saturday nights there is also a 30 minutes service throughout the night.
History
Since the first part of the Køge radial opened in 1972, letter A has been used for the principal service on its inner part. Before that time the most constant characteristic of service A was that it ran on the Klampenborg radial in the northern end of the system.| Name | Southern end | Years | Northern end |
| 1a | all stops to Valby | 1934–1940 | Klampenborgbanen: all stops to Klampenborg |
| 1a | terminated at København H | 1940–1950 | Klampenborgbanen: all stops to Klampenborg |
| A | Frederikssundbanen: all stops to Vanløse | 1950–1952 | Klampenborgbanen: all stops to Klampenborg |
| A | as above, extended to Herlev in rush hours | 1952–1972 | Klampenborgbanen: all stops to Klampenborg |
| A | Køgebugtbanen: all stops to Vallensbæk | 1972–1976 | Klampenborgbanen: all stops to Klampenborg |
| A | all stops to Hundige | 1976–1979 | Klampenborgbanen: all stops to Klampenborg |
| A | all stops to Hundige; extended to Solrød Strand evenings and weekends | 1979–1983 | Nordbanen: all stops to Holte |
| A | all stops to Hundige | 1983–1989 | Nordbanen: all stops to Holte |
| A | all stops to Hundige | 1989–1999 | Nordbanen: to Hillerød, non-stop Østerport-Hellerup-Lyngby-Holte |
| A | all stops to Hundige | 1999–2007 | as above except all stops until Hellerup |
| A | all stops to Hundige | 2007–2009 | Hareskovbanen: all stops to Farum |
| A | all stops to Hundige; some daytime trains to Solrød Strand | Dec 2009– | Hareskovbanen: all stops to Farum |