S-Train

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**S-train**

Locale	Metropolitan Copenhagen
Transit type	Commuter rail
Began operation	1934
No. of lines	7 with 11 services
No. of stations	85
Daily ridership	240,000 daily (approximately)
Track gauge	1435 mm (4 ft 8½ in)
Operator	DSB S-tog

The S-Train (S-tog) network is the commuter train network of Metropolitan Copenhagen, Denmark. It connects the city center with the suburbs of Copenhagen. The first line was built in 1934. Today the network forms the heart of the public transportation infrastructure in the city, serving more than 240,000 passengers a day. It is entirely owned and run by DSB S-tog A/S.

The system is complemented by the Copenhagen Metro and an extensive bus network. Although owned by different companies, all three systems use interchangeable tickets. Most of the city's terminals are located adjacent to an S-train station.

In the city center, the trains run below ground level with one underground station. Outside the inner city it runs in the open, often on embankments. Although the S-trains run parallel to the regional/intercity mainline tracks between Høje Tåstrup and Klampenborg, it has its own separate trackage all the way with different signalling and power standards than the mainline tracks. A handful of track connections between S-train and mainline tracks exist but are used only in special circumstances (mostly by maintenance vehicles).

The official diagram showing S-train services is a well-known icon for the S-trains network

1 Network
- 1.1 Services
2 Technical overview
3 See also
4 External links

[edit] Network

The network consists of a central section that splits into three radial lines at each end. The southern radials are

Køgebugtbanen to Hundige and Køge
Vestbanen to Høje Taastrup
Frederikssundbanen to Ballerup and Frederikssund

The northern radials are

Hareskovbanen to Farum
Nordbanen to Holte and Hillerød
Klampenborgbanen to Klampenborg

The six radials are additionally connected by

Ringbanen, the "ring line"

See articles about each of the seven components for station lists and service patterns.

[edit] Services

The current timetable (January 2006) organizes the trains on the network into 11 services, each with a letter designation. Each service runs on a strict 20-minute frequency.

The spine of the network are basic services that run all days from about 05.00 to about 01.00. They are named with single letters. The basic services are supplemented by plus services which generally run on weekdays until about 19.00. There used to be several rush-hour services designated with an x suffix, but most have been replaced by plus lines, and only a single one remains.

Name	Southern end		Runs when	Northern end
A	all stops to Hundige	Køgebugtbanen	All week, all day	Nordbanen	limited stops to Holte, then all stops to Hillerød
A+	almost all stops to Køge	Køgebugtbanen	Mo-Fr, daytime	Hareskovbanen	all stops to Buddinge
A+	almost all stops to Køge	Køgebugtbanen	Sat, daytime	(terminates at Østerport)
B	all stops to Høje Taastrup	Vestbanen	All week, all day	Nordbanen	all stops to Holte
B+	all stops to Høje Taastrup	Vestbanen	Mo-Sa, daytime	Nordbanen	all stops to Holte
C	all stops to Ballerup	Frederikssundbanen	All week, all day	Klampenborgbanen	all stops to Klampenborg
E	limited stops to Hundige, then all stops to Køge	Køgebugtbanen	Mo-Sa, daytime	Nordbanen	limited stops to Holte, then all stops to Hillerød
E	limited stops to Hundige, then all stops to Køge	Køgebugtbanen	All other times	Nordbanen	limited stops to Lyngby
Ex	limited stops from Køge only	Køgebugtbanen	Mo-Fr morning	(terminates at Østerport)
F	all stops	Ringbanen	All week, all day
F+	all stops	Ringbanen	All week, daytime	Klampenborgbanen	all stops Hellerup-Klampenborg
F+	all stops	Ringbanen	All other times	(terminates at Hellerup)
H	limited stops to Ballerup, then all stops to Frederikssund	Frederikssundbanen	All week, all day	Hareskovbanen	all stops to Farum
H+	all stops to Frederikssund	Frederikssundbanen	Mo-Sa, daytime	Hareskovbanen	limited stops to Farum

[edit] Technical overview

Valby station with 4th-generation S-train

2nd generation S-Train from 1971.

The S-trains run on standard gauge railway tracks and are powered by overhead wires. The voltage is variously quoted as 1500 [1] or 1650 [2] volts DC, which indicates that it varies considerably with the loading and distance from a feeder station. Power is drawn from the national grid through 38 feeder stations spread around the network. The feeder stations have to be relatively close to each other because the large currents in the overhead wires (caused by the relatively low voltage) would lead to unacceptably large transmission losses otherwise.

The primary signalling system is a fixed-block cab signalling system called HKT which transmits data to the trains through low-bandwidth audio frequency induction loops between the rails. Different frequency combinations encode different target speeds; when a train enters a block with a lower target speed than its current speed it will initiate a service braking until the two match. This allows blocks to be much shorter than the full-speed braking distance, but as the braking profile is encoded in the transmitted target speed it only works where all trains have similar braking characteristics.

Lineside light signals are also provided for use in case of HKT failures or the occasional visit of a non-S-Train, but the lineside blocks are longer, so capacity in this mode is reduced. As of 2006 a small part of the network (Lyngby–Hillerød) are not yet equipped with HKT and all movements are signalled with lineside signals.

The trains are 8-car articulated units (DSB class SA-SD) supplied by Linke-Hofmann-Busch/Siemens. The cars are shorter than conventional railway cars; each has a single axle under one end of the car; the other end is supported by the neighbouring car. (The end cars are exceptions and have two axles each). The units have automatic scharfenberg couplers at the ends; in peak hours most trains consist of two coupled units. There are also a small number of 4-car units (class SE-SH) that can run solo in low-traffic intervals.

As of 2006 there are still a number of older units in use (DSB class MM-FU-MU-FS and FC-MC-MC-FC). These are 4-car sets with the same length as a newer 8-car unit; each car has two bogies with a total of four axles. They are retired and scrapped as new units are delivered.