The Sm4

electric multiple unit An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number ...

(EMU) is a low-floor train used by the

VR Group VR-Group Plc ( fi, VR-Yhtymä Oyj, sv, VR-Group Abp), commonly known as VR, is a government-owned railway company in Finland. VR's most important function is the operation of Finland's passenger rail services with 250 long-distance and 800 co ...

for longer-distance

Helsinki commuter rail Helsinki commuter rail ( fi, Helsingin seudun lähijunaliikenne, sv, Huvudstadsregionens närtrafik) is a commuter rail system serving Greater Helsinki and the surrounding county of Uusimaa. The system is a joint venture between the regional t ...

services. The initial order was for ten EMUs with the first unit entering service in 1999. Another 20 units were ordered in 2002 and the deliveries were completed in 2005. The Spanish company CAF was contracted to manufacture the units, based on a design by

Alstom Alstom SA is a French multinational corporation, multinational rolling stock manufacturer operating worldwide in rail transport markets, active in the fields of passenger transportation, signalling, and locomotives, with products including the A ...

Features

The Sm4 EMU consists of two powered cars, each equipped with a

pantograph A pantograph (, from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line dr ...

. The unit is capable of

regenerative braking Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction mo ...

and can thereby save up to 30% of the

electrical energy Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and elect ...

that would otherwise be consumed. The maximum speed is . The unit offers a good level of passenger comfort with a quiet and smooth ride quality. The Sm4 passenger compartments are fitted with

air conditioning Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...

CCTV Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly ...

cameras and display screens that can be used to show e.g. route information. The units have partly low floors with all of the entrances at platform level, and they are equipped with toilets accessible to the disabled. There are racks for bicycles in the entrance vestibules nearest to the driver's cabins. Trains are usually formed of two units, but also only one and up to four in the peak hours, when traffic is too high to increase capacity by higher frequency of trains. This allows for a flexible handling of varying passenger traffic. The maximum number of connected units is five.

Routes

The Sm4 is designed for longer-distance trips than typical metro-like local services. The Sm4 units have largely replaced the older Sm1 and Sm2 units on commuter services from

Helsinki Helsinki ( or ; ; sv, Helsingfors, ) is the Capital city, capital, primate city, primate, and List of cities and towns in Finland, most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of U ...

Riihimäki Riihimäki (literally "Drying barn hill") is a town and municipality in the south of Finland, about north of Helsinki and southeast of Tampere. An important railway junction is located in Riihimäki, since railway tracks from Riihimäki lead to ...

and

Lahti Lahti (; sv, Lahtis) is a city and municipality in Finland. It is the capital of the region of Päijänne Tavastia (Päijät-Häme) and its growing region is one of the main economic hubs of Finland. Lahti is situated on a bay at the southern e ...

. The units are also used in commuter traffic on the

Tampere Tampere ( , , ; sv, Tammerfors, ) is a city in the Pirkanmaa region, located in the western part of Finland. Tampere is the most populous inland city in the Nordic countries. It has a population of 244,029; the urban area has a population ...

–Riihimäki and Riihimäki–

Kouvola Kouvola () is a city and municipality in southeastern Finland. It is located along the Kymijoki River in the region of Kymenlaakso, kilometers east of Lahti, west of Lappeenranta and northeast of the capital, Helsinki. With Kotka, Kouvola is ...

routes. The Sm4s were also used for the shorter, frequently-stopping services because of the lack of more suitable low floor trains. The new Sm5 low floor trains that started to enter commercial service in November 2009 have completely replaced the Sm4 units on the short routes.

Nickname

Some railway enthusiasts use the nickname ''Pupu'' ("Bunny") for Sm4.

References

External links

* {{Finnish locomotives Multiple units of Finland 25 kV AC multiple units CAF multiple units Alstom multiple units Alstom Coradia