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 o ...

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

VR Group VR-Group Plc (, ), 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 commuter rail services every day. With ...

for its

VR commuter rail VR commuter rail (, ) is a Finland, Finnish Regional rail, commuter rail system operated by VR Group, VR – the Railway company, national railway operator of Finland – under a public service obligation agreement with the Ministry of Transport ...

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 Fiat Ferroviaria (later acquired by

Alstom Alstom SA () is a French multinational rolling stock manufacturer which operates worldwide in rail transport markets. It is active in the fields of passenger transportation, signaling, and locomotives, producing high-speed, suburban, regional ...

). The train has the nickname of pupu, meaning bunny in English.

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 Linkage (mechanical), 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 se ...

. 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 or potential energy into a form that can be either used immediately or stored until needed. Typically, regenerativ ...

and can thereby save up to 30% of the

electrical energy Electrical energy is the energy transferred as electric charges move between points with different electric potential, that is, as they move across a voltage, potential difference. As electric potential is lost or gained, work is done changing the ...

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 (US) or air con (UK), is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature, and in some cases, also controlling the humidity of internal air. Air c ...

CCTV Closed-circuit television (CCTV), also known as video surveillance, is the use of closed-circuit television cameras to transmit a signal to a specific place on a limited set of monitors. It differs from broadcast television in that the signa ...

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 () is the Capital city, capital and most populous List of cities and towns in Finland, city in Finland. It is on the shore of the Gulf of Finland and is the seat of southern Finland's Uusimaa region. About people live in the municipali ...

Riihimäki Riihimäki (; ) 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 Helsinki, Tampere and La ...

and

Lahti Lahti (; ) is a city in Finland and the regional capital of Päijät-Häme. It is located in the Finnish Lakeland. The population of Lahti is approximately , while the Lahti sub-region, sub-region has a population of approximately . It is the mo ...

. The units are also used in commuter traffic on the

Tampere Tampere is a city in Finland and the regional capital of Pirkanmaa. It is located in the Finnish Lakeland. The population of Tampere is approximately , while the metropolitan area has a population of approximately . It is the most populous mu ...

–Riihimäki and Riihimäki–

Kouvola Kouvola () is a city in Finland and the administrative capital of Kymenlaakso. It is located in the southeastern interior of the country. The population of Kouvola is approximately . It is the most populous municipality in Finland, and the 17th m ...

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 HSL commuter rail routes.

References

External links

* {{Finnish locomotives Multiple units of Finland 25 kV AC multiple units CAF multiple units Alstom multiple units Alstom Coradia Train-related introductions in 1999