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Tram

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A tram is a specific type of urban rail transit system.

Zuerich-vbz-tram-2-swpsigbbc-880755
Zuerich-vbz-tram-2-swpsigbbc-880755

These vehicles run on tramway tracks located on public city streets. They are considered a form of light rail. However, they differ from heavy rail or rapid transit in several ways. Trams are often integrated directly into urban streets. They coexist with other vehicles like cars and buses. They also have lower traffic signal priority and lower passenger capacity. Some systems include segments of segregated right-of-way, where the tracks are kept separate from other traffic.

New Flexity LR vehicles approach Spadina and King, 2016 07 21 (15).JPG - panoramio
New Flexity LR vehicles approach Spadina and King, 2016 07 21 (15).JPG - panoramio

To move, most modern trams rely on electrical power. This energy is usually supplied by an overhead line. A device called a pantograph slides along this wire to collect electricity.

Tramway graz03
Tramway graz03

Older systems might use a trolley pole or a bow collector to reach the wire. In some specific cases, a contact shoe is used on a third rail. Some vehicles use dual power systems to increase their range. They might use electricity while in city streets and switch to diesel in rural areas. Occasionally, trams are even used to carry freight instead of just people.

There are several ways to categorize these rail systems. Trams can consist of individual railcars or multiple-unit trains. When units are linked together, they form motor coaches or motorcars to create longer trains. Some specialized versions are called tram-trains. These can run on segments of mainline railway tracks, much like interurban systems. The differences between these modes are often indistinct. Many modern systems combine multiple features from different types of rail transport.

Daejeon-metro-tram-train--built-by-hyundai-rotem--on-innotrans-fair--2024-09-24--picture-by-georgr--cc-by-sa
Daejeon-metro-tram-train--built-by-hyundai-rotem--on-innotrans-fair--2024-09-24--picture-by-georgr--cc-by-sa

The history of the tram began with early precursors like wooden or stone wagonways. These were used in central Europe since the 1500s to move mine carts. By the 1700s, England introduced paved plateways with cast iron rails to move coal and iron ore. The first passenger tram service was the Swansea and Mumbles Railway in Wales. The British Parliament passed the Mumbles Railway Act in 1804, and service began in 1807.

Horsetrain 1870
Horsetrain 1870

Street railways actually developed in America before Europe. This was because American streets were poorly paved and unsuitable for horsebuses. Running horsecars on rails provided a much smoother ride for passengers.

Early passenger trams relied heavily on animal power. In the United States, the New York and Harlem Railroad began service in 1832.

The last of the Horse Drawn Carriages
The last of the Horse Drawn Carriages

Using horses presented many logistical challenges. A single horse could only work about four or five hours a day. Each animal required constant feeding, grooming, and housing. Companies also had to manage the massive amounts of manure produced by the animals. Because of these high costs, electric trams began to replace animal power in the late 19th and early 20th centuries. Some horse-drawn systems lasted a long time, such as the mule tram in Celaya, Mexico, which survived until 1954.

Mechanical power evolved from steam to electricity. The first mechanical trams used steam engines. There were two main types of steam trams. The first type used a small steam locomotive to pull a line of carriages.

Bruehl Feuriger Elias
Bruehl Feuriger Elias

The second type had the steam engine built directly into the body of the tram. These were called tram engines in the UK or steam dummies in the US. Eventually, electric systems became the standard. The first electric tram was demonstrated by Siemens in 1881.

First electric tram- Siemens 1881 in Lichterfelde
First electric tram- Siemens 1881 in Lichterfelde

Trams saw a decline in the mid-20th century due to better buses, but they have seen a resurgence since the 1980s.

One major scientific advantage of the tram is low rolling resistance. This refers to the reduced friction between the metal wheels and the steel rails.

Szyny Głogowska RB2
Szyny Głogowska RB2

Because the resistance is low, a tram can haul a much greater load with less effort. This efficiency helped the technology spread globally. The first permanent line in continental Europe opened in Paris in 1855. Santiago, Chile, opened its first tram in 1858. Sydney, Australia, started service in 1860. Africa's first service began in Alexandria in 1863, and Asia's first opened in Batavia in 1869. These systems remain vital parts of urban infrastructure today.

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Go by Streetcar sign - Portland Oregon.jpg
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File:Horsetrain 1870.jpg
Horsetrain 1870.jpg
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Milano inauguraz tram Monza.jpg
File:The last of the Horse Drawn Carriages.JPG
The last of the Horse Drawn Carriages.JPG
File:Bruehl Feuriger Elias.jpg
Bruehl Feuriger Elias.jpg
File:Minories stationLBR.jpg
Minories stationLBR.jpg
File:Melbourne’s first cable tram.jpg
Melbourne’s first cable tram.jpg
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San Francisco Cable Car MC.jpg
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Bensinmotorvagn. Trafikerade linjen 19,...
File:First electric tram- Siemens 1881 in Lichterfelde.jpg
First electric tram- Siemens 1881 in...
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Blackpool + zoo 1979 to 1980 (32963118752).jpg

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