Trolleybus

A trolleybus (also known as trolley bus, trolley coach, trackless

trolley, trackless tram – in the 1910s and 1920s[1] – or trolley[2][3])
is an electric bus that draws power from dual overhead wires
(generally suspended from roadside posts) using spring-loaded trolley
poles. Two wires, and two trolley poles, are required to complete the
electrical circuit. This differs from a tram or streetcar, which normally
uses the track as the return path, needing only one wire and one pole
(or pantograph). They are also distinct from other kinds of electric
buses, which usually rely on batteries. Power is most commonly Busscar trolleybus in São Paulo,
supplied as 600-volt direct current, but there are exceptions. Brazil

Currently, around 300 trolleybus systems are in operation, in cities

and towns in 43 countries.[4] Altogether, more than 800 trolleybus
systems have existed, but not more than about 400 concurrently.[5]

History
The trolleybus dates back to 29 April 1882, when Dr. Ernst Werner
Siemens demonstrated his "Elektromote" in a Berlin suburb.[7] This
experiment continued until 13 June 1882, after which there were few Solaris trolleybus in Landskrona,
developments in Europe, although separate experiments were Sweden
[8]
conducted in the United States. In 1899, another vehicle which
could run either on or off rails was demonstrated in Berlin.[9] The next
development was when Louis Lombard-Gérin operated an
experimental line at the Paris Exhibition of 1900 after four years of
trials, with a circular route around Lake Daumesnil that carried
passengers. Routes followed in six places including Eberswalde and
Fontainebleau.[10] Max Schiemann on 10 July 1901 opened the
world's fourth passenger-carrying trolleybus system, which operated
at Bielatal (Biela Valley, near Dresden), Germany. Schiemann built
and operated the Bielatal system, and is credited with developing the Video of a trolleybus in Ghent,
under-running trolley current collection system, with two horizontally Belgium
parallel overhead wires and rigid trolleypoles spring-loaded to hold
them up to the wires. Although this system operated only until 1904,
Schiemann had developed what is now the standard trolleybus current collection system. In the early days
there were many other methods of current collection.[8] The Cédès-Stoll (Mercédès-Électrique-Stoll) system
was first operated near Dresden between 1902 and 1904, and 18 systems followed. The Lloyd-Köhler or
Bremen system was tried out in Bremen with 5 further installations, and the Cantono Frigerio system was
used in Italy.

Throughout this period, trackless freight systems and electric canal boats were also built.
Leeds and Bradford became the first cities to put trolleybuses into
service in Great Britain, on 20 June 1911.[9] Supposedly, though it
was opened on 20 June, the public was not admitted to the Bradford
route until the 24th. Bradford was also the last city to operate
trolleybuses in the UK; the system closed on 26 March 1972. The last
rear-entrance trolleybus in service in Britain was also in Bradford and
is now owned by the Bradford Trolleybus Association. Birmingham
was the first UK city to replace a tram route with trolleybuses, while
Wolverhampton, under the direction of Charles Owen Silvers, became
The "Elektromote", the world's first
world-famous for its trolleybus designs.[11] There were 50 trolleybus
trolleybus,[6] in Berlin, Germany,
systems in the UK, London's being the largest. By the time 1882
trolleybuses arrived in Britain in 1911, the Schiemann system was
well established and was the most common, although the Cédès-Stoll
(Mercédès-Électrique-Stoll) system was tried in West Ham (in 1912)
and in Keighley (in 1913).[12][13]

Smaller trackless trolley systems were built in the US early as well.

The first non-experimental system was a seasonal municipal line
installed near Nantasket Beach in 1904; the first year-round
commercial line was built to open a hilly property to development just
outside Los Angeles in 1910. The trackless trolley was often seen as A double-deck trolleybus in
an interim step, leading to streetcars. In the US, some systems Reading, England, 1966
subscribed to the all-four concept of using buses, trolleybuses,
streetcars (trams, trolleys), and rapid transit subway and/or elevated
lines (metros), as appropriate, for routes ranging from the lightly used to the heaviest trunk line. Buses and
trolleybuses in particular were seen as entry systems that could later be upgraded to rail as appropriate. In a
similar fashion, many cities in Britain originally viewed trolleybus routes as extensions to tram (streetcar)
routes where the cost of constructing or restoring track could not be justified at the time, though this attitude
changed markedly (to viewing them as outright replacements for tram routes) in the years after 1918.[14]
Trackless trolleys were the dominant form of new post-World War I electric traction, with extensive systems
in among others, Los Angeles, Chicago, Boston, Rhode Island, and Atlanta; San Francisco and Philadelphia
still maintain an "all-four" fleet. Some trolleybus lines in the United States (and in Britain, as noted above)
came into existence when a trolley or tram route did not have sufficient ridership to warrant track
maintenance or reconstruction. In a similar manner, a proposed tram scheme in Leeds, United Kingdom, was
changed to a trolleybus scheme to cut costs.[15]

Trolleybuses are uncommon today in North America, but their

use is widespread in Europe and Russia. They remain common in
many countries which were part of the Soviet Union.[16]
Generally trolleybuses occupy a position in usage between street
railways (trams) and motorbuses. Worldwide, around 300 cities
or metropolitan areas on 5 continents are served by trolleybuses
(further detail under Use and preservation, below).

This mode of transport operates in large cities, such as Belgrade,

MU ZiU-9 in Soviet Union, 1987
Lyon, Pyongyang, São Paulo, Seattle, Sofia, St. Petersburg, and
Zurich, as well as in smaller ones such as Dayton, Gdynia,
Lausanne, Limoges, Modena, and Salzburg. As of 2020, Kyiv has, due to its history in the former Soviet
Union, the largest trolleybus system in the world in terms of route length while another formerly Soviet city,
Minsk, has the largest system in terms of number of routes (which
also date back to the Soviet era).[17] Landskrona has the smallest
system in terms of route length, while Mariánské Lázně is the
smallest city to be served by trolleybuses. Opened in 1914, Shanghai's
trolleybus system is the oldest operating system in the world. With a
length of 86 km, route #52 of Crimean Trolleybus is the longest
trolleybus line in the world. See also Trolleybus usage by country.
The Shanghai trolleybus system is
currently the oldest in the world.
Transit authorities in some cities have reduced or discontinued the use
of trolleybuses in recent years, while others, wanting to add or expand
use of zero-emission vehicles in an urban environment, have opened
new systems or are planning new systems. For example, new systems
opened in Lecce, Italy, in 2012; in Malatya, Turkey, in 2015;[18] and
in Marrakesh, Morocco, in 2017.[19] Beijing and Shanghai have been
expanding their respective systems, with Beijing expanding to a 31-
line system operated with a fleet of over 1,250 trolleybuses.[20]
Trolleybuses have been long encouraged in North Korea with the
newest city to have a network being Manpo in December 2019.[21] Some coal mines also operate
Since the year 2022, the city of Prague is constructing a new separate trolleybus systems to
trolleybus system.[22] Meanwhile, in 2023, plans for a trolleybus line serve workers. Wuyang Coal Mine
in Berlin were scrapped in favour of a solution with battery-powered in Xiangyuan, Changzhi, Shanxi has
vehicles.[23] the last remaining mine trolleybus
system in China.

Vehicle design

1. Parallel overhead
lines (overhead
wires)
2. Destination or route
sign
3. Rear view mirror
4. Headlights
5. Boarding (entry)
doors
6. Direction (turning)
wheels
Diagram of a 1947-built Pullman Standard model 800 trolleybus, a type still running 7. Exit doors
in Valparaíso (Chile) 8. Traction wheels
9. Decorative
elements
10. Retractors/retrievers
11. Pole rope
12. Contact shoes
13. Trolley poles (power
collector)
14. Pole storage hooks
15. Trolley pole base
 and fairing/shroud
16. Bus number
Modern design vehicles

Irisbus Cristalis in Van Hool Exquicity 18T AKSM-420 Vitovt in

Limoges in Parma Minsk

New Flyer XT60 in Seattle Youngman JNP6183BEV Solaris Trollino 18 in

in Beijing Salzburg

Trolleybus in Castellón de Trolleybus in Malatya

la Plana

Advantages

Comparison to trams
Cheaper infrastructure – The initial start up cost of trams is much higher, due to rail, signals,
and other infrastructure. Trolleybuses can pull over to the kerb like other buses, eliminating the
need for special boarding stations or boarding islands in the middle of the street, thus stations
can be moved as needed.
Better hill climbing – Trolleybuses' rubber tyres have better adhesion than trams' steel wheels
on steel rails, giving them better hill-climbing capability and braking.
Easier traffic avoidance – Unlike trams (where side tracks are often unavailable), an out-of-
service vehicle can be moved to the side of the road and its trolley poles lowered. The ability to
drive a substantial distance from the power wires allows trackless vehicles to avoid obstacles,
although it also means a possibility that the vehicle may steer or skid far enough that the trolley
pole can no longer reach the wire, stranding the vehicle. Trackless trolleys also are able to
avoid collisions by manoeuvring around obstacles, similar to motor buses and other road
vehicles, while trams can only change speed.
 Quietness – Trolleybuses are generally quieter than trams.
Easier training – The control of trolleybuses is relatively
similar to motorbuses; the potential operator pool for all
buses is much larger than for trams.

Comparison to motorbuses
Better hill climbing – Trolleybuses are better than
motorbuses on hilly routes, as electric motors provide much
higher static torque at start-up, an advantage for climbing
steep hills. Unlike internal combustion engines, electric
motors draw power from a central plant and can be
overloaded for short periods without damage. San
Francisco and Seattle, both hilly American cities, use
trolleybuses partly for this reason. Given their acceleration A San Francisco Muni trolleybus
and braking performance, trolleybuses can outperform (ETI 14TrSF) climbing Nob Hill
diesel buses on flat stretches as well, which makes them
better for routes that have frequent stops.
Environmentally friendly – Trolleybuses are usually more
environmentally friendly in the city than fossil fuel or
hydrocarbon-based vehicles (petrol/gasoline, diesel,
alcohol, etc.). Power from a centralized plant, even taking
into account transmission losses, is often produced more
efficiently, is not bound to a specific fuel source, and is
more amenable to pollution control as a point source, unlike
individual vehicles with exhaust gases and particulates at
street level. Trolleybuses are especially favoured where
electricity is abundant, cheap, and renewable, such as Trolleybus on tunnel line in
hydroelectric. Systems in Seattle and in Vancouver, BC, Tateyama
draw hydroelectric power from the Columbia River and
other Pacific river systems. San Francisco operates its
system using hydro power from the city-owned Hetch
Hetchy generating plant.
Trolleybuses can generate electricity from kinetic energy
while braking, a process known as regenerative braking.
For regenerative braking to function, there must be another
bus on the same circuit needing power, an electric storage
system on the vehicle or the wire system, or a method to
send the excess power back to the commercial electric
power system. Otherwise the braking energy must be
dissipated in resistance grids on the bus; this is called
Underground trolleybus at Kurobe
"dynamic braking". The use of trolley buses also eliminates
pollution during idling, thus improving air quality. Dam Station

Minimal noise pollution – Unlike trams or gasoline and

diesel buses, trolleybuses are almost silent, lacking the
noise of a combustion engine or wheels on rails. Most noise comes from auxiliary systems
such as power steering pumps and air conditioning. Early trolleybuses without these systems
were even quieter and in the United Kingdom were sometimes referred to as the "Silent
Service". This however can also be seen as a disadvantage, with some pedestrians falling
victim to what was known as "Silent Death" (in Britain) or "Whispering Death" (in Australia).
Usable in enclosed space – The absence of exhaust gases allows trolleybuses to operate
underground. In Cambridge, Massachusetts, trackless trolleys survived because Harvard
Station, where several bus lines terminate, is in a tunnel once used by streetcars. Although
diesel buses do use the tunnel, there are limitations due to exhaust fumes, which running the
trolleybuses through aids in ventilation. Also, the trackless trolleys continue to have popular
 support. The only trolleybus systems in Japan, the Tateyama Tunnel Trolleybus and Kanden
Tunnel Trolleybus lines, both run in tunnels serving the Kurobe Dam and Tateyama Kurobe
Alpine Route, and were converted from normal diesel buses specifically for their lack of
exhaust.
Longevity and maintenance – Electric motors typically last longer than internal combustion
motors, and cause less secondary damage from vibration, so electric buses tend to be very
long-lived compared to motorbuses. As the basic construction of buses has not changed much
in the last 50 plus years, they can be upgraded such as when air conditioning was retrofitted to
many trolleybuses. Such upgrades are often disproportionately expensive. Wheelchair lifts are
relatively simple to add; kneeling front suspension is a common feature of air suspension on
the front axle in lieu of springs. In comparison to battery-powered buses, the lack of a specially
designed battery or fuel cell (typically with expensive patents) decreases the price and weight,
and in locations with a sufficient power delivery network, the trolleybus is cheaper and easier to
maintain in comparison to those requiring charging stations.

Disadvantages

Comparison to trams
Note: As there are numerous variations of tram and light-rail
technology, the disadvantages listed may be applicable only with a
specific technology or design.
A Rocar DAC 217E articulated
trolleybus in Bucharest, Romania, in
Like any bus, much less capacity than trams. April 2007
More control required – Trolleybuses must be driven like
motorbuses, requiring directional control by the driver.
Higher rolling resistance – Rubber-tired vehicles generally
have more rolling resistance than steel wheels, which
decreases energy efficiency.
Less efficient use of right-of-way – Lanes must be wider for
unguided buses than for streetcars, since unguided buses
can drift side-to-side. The use of guidance rail allows trams
running in parallel lanes to pass closer together than drivers
could safely steer.
Difficulties with platform loading – Implementation of level
platform loading with minimal gap, either at design stage or Pole bases with springs and
afterwards, is easier and cheaper to implement with rail pneumatic pole lowering cylinders
vehicles.
Wear of rubber tires leads to significant rubber pollution.

Comparison to motorbuses
Difficult to re-route – When compared to motorbuses, trolleybuses have greater difficulties with
temporary or permanent re-routings, wiring for which is not usually readily available outside of
downtown areas where the buses may be re-routed via adjacent business area streets where
other trolleybus routes operate. This problem was highlighted in Vancouver in July 2008,[24]
when an explosion closed several roads in the city's downtown core. Because of the closure,
trolleys were forced to detour several miles off their route in order to stay on the wires, leaving
major portions of their routes not in service and off-schedule.
Aesthetics – The jumble of overhead wires may be seen as unsightly.[25] Intersections often
have a "webbed ceiling" appearance, due to multiple crossing and converging sets of trolley
wires.
 Dewirements – Trolley poles sometimes come off the wire.
Dewirements are relatively rare in modern systems with
well-maintained overhead wires, hangers, fittings and
contact shoes. Trolleybuses are equipped with special
insulated pole ropes which drivers use to reconnect the
trolley poles with the overhead wires. When approaching
switches, trolleybuses usually must decelerate in order to
avoid dewiring, and this deceleration can potentially add
slightly to traffic congestion. In 1998, a dewirement in
Shenyang on poorly maintained infrastructure killed 5
people and ultimately led to the destruction of the trolleybus
network.[26]
Unable to overtake other trolleybuses – Trolleybuses
cannot overtake one another in regular service unless two
separate sets of wires with a switch are provided or the
vehicles are equipped with off-wire capability, with the latter
an increasingly common feature of new trolleybuses.
Insulated poles, contact shoes, and
Higher capital cost of equipment – Trolleybuses are often
pull–ropes
long-lived equipment, with limited market demand. This
generally leads to higher prices relative to internal
combustion buses. The long equipment life may also
complicate upgrades.
More training required – Drivers must learn how to prevent dewiring, slowing down at turns and
through switches in the overhead wire system, for example.[27]
Overhead wires create obstruction – Trolleybus systems employ overhead wires above the
roads, often shared with other vehicles. The wires can restrict tall motor vehicles such as
delivery trucks ("lorries") and double decker buses from using or crossing roads fitted with
overhead wires, as such vehicles would hit the wires or pass dangerously close to them, risking
damage and dangerous electrical faults. The wires also may impede positioning of overhead
signage and create a hazard to activities such as road repairs using tall excavators or piling
rigs, use of scaffolding, etc.

Off-wire power developments

With the re-introduction of hybrid designs, trolleybuses are no longer
tied to overhead wires. The Public Service Company of New Jersey,
with Yellow Coach, developed "All Service Vehicles"; trackless
trolleys capable of operating as gas-electric buses when off wire, and
used them successfully between 1935 and 1948. Since the 1980s,
systems such as Muni in San Francisco, TransLink in Vancouver, and
Beijing, among others, have bought trolleybuses equipped with
batteries to allow them to operate fairly long distances away from the
wires. Supercapacitors can be also used to move buses short
distances.

Trolleybuses can optionally be equipped either with limited off-wire

capability—a small diesel engine or battery pack—for auxiliary or
On this articulated Beijing trolleybus, emergency use only, or full dual-mode capability. A simple auxiliary
the operator uses ropes to guide the
power unit can allow a trolleybus to get around a route blockage or
trolley poles to contact the overhead
wires.
can reduce the amount (or complexity) of overhead wiring needed at
operating garages (depots). This capability has become increasingly
common in newer trolleybuses, particularly in China, North America
and Europe, where the vast majority of new trolleybuses delivered since the 1990s are fitted with at least
limited off-wire capability. These have gradually replaced older trolleybuses which lacked such capability. In
Philadelphia, new trackless trolleys equipped with small hybrid diesel-electric power units for operating
short distances off-wire were placed in service by SEPTA in 2008. This is instead of the trolleys using a
conventional diesel drive train or battery-only system for their off-wire movement.[28]

King County Metro in Seattle, Washington and the MBTA in Boston's

Silver Line have used dual-mode buses that run on electric power
from overhead wires on a fixed right-of-way and on diesel power on
city streets. Metro used special-order articulated Breda buses,
introduced in 1990, and most were retired in 2005. A limited number
of the Breda dual-mode buses had their diesel engines removed, and
operated exclusively as trolleybuses until 2016.[29] Since 2004, the
MBTA has used dual-mode buses on its Silver Line (Waterfront) A dual-mode bus operating as a
route. The last of these were be replaced by diesel hybrid and battery- trolleybus in the Downtown Seattle
electric buses in June 2023.[30] Transit Tunnel, in 1990

In Motion Charging
IMC (In Motion Charging) trolleybuses are equipped with a light-
weight battery, the size of which is adapted to the line profile used.
This battery allows them not to depend on overhead lines. They can
thus operate with a mix of electric wire and batteries (60% of the time
on the wire and 40% on the battery). With the development of battery
technology in recent years, trolleybuses with extended off-wire Trolleybus with battery pack and full
dual-mode capability on the streets
capability through on-board batteries are becoming popular. The on-
of Brest, Belarus
board battery is charged while the vehicle is in motion under the
overhead wires and then allows off-wire travel for significant
distances, often in excess of 15 km.[31][32] Such trolleybuses are
called, among others, trolleybuses with In-Motion Charging, hybrid
trolleybuses, battery trolleybuses and electric buses with dynamic
charging. The main advantages of this technology over conventional
battery electric buses are reduced cost and weight of the battery due to
its smaller size, no delays for charging at end stops as the vehicle
charges while in motion and reduced need for dedicated charging In Motion Charging additional
stations that take up public space. This new development allows the batteries charging at Palmovka
extension of trolleybus routes or the electrification of bus routes Prague
without the need to build overhead wires along the whole length of
the route. Cities that utilize such trolleybuses include Beijing,[33]
Ostrava,[32] Shanghai,[31] Mexico City,[34] Saint Petersburg,[35] and Bergen.[36] The new trolleybus systems
in Marrakesh, Baoding[37] and Prague are based exclusively on battery trolleybuses. In 2020, the city of
Berlin, Germany announced plans to build a new trolleybus system with 15 routes and 190 battery
trolleybuses.[38] However, in early 2023 it was announced that the planned lines would use battery powered
electric buses instead.[23]

Introducing new flexible, high-capacity public transport of in motion charging (IMC) trolleybuses are
electric buses that can charge dynamically via an overhead contact network and can run on batteries for up to
half of their route. Because an IMC bus is operated electrically just as a tramcar without limitation of the
range. It concept of trolleybus and ebus with Battery electric bus. IMC500 transfers energy from the
infrastructure to the vehicle at a power of up to 500 kW. The e.g. 2 x 160 kW motors are supplied in parallel
to the battery charging with e.g. 200 kW.[39][40]

Other considerations
With increasing diesel fuel costs and problems caused by particulate matter and NOx emissions in cities,
trolleybuses can be an attractive alternative, either as the primary transit mode or as a supplement to rapid
transit and commuter rail networks.

Trolleybuses are quieter than internal combustion engine vehicles. Mainly a benefit, it also provides much
less warning of a trolleybus's approach. A speaker attached to the front of the vehicle can raise the noise to a
desired "safe" level. This noise can be directed to pedestrians in front of the vehicle, as opposed to motor
noise which typically comes from the rear of a bus and is more noticeable to bystanders than to pedestrians.

Trolleybuses can share overhead wires and other electrical infrastructure (such as substations) with
tramways. This can result in cost savings when trolleybuses are added to a transport system that already has
trams, though this refers only to potential savings over the cost of installing and operating trolleybuses alone.

The two parallel wires

The wires are attached to poles next to the street and carefully stretched and mounted so that they are the
same width apart and same height over the road (usually about 18 to 20 feet (~5.7m)). The pair of wires is
insulated from the poles and provides about 500 to 600 volts to the bus below.[41]

Wire switches
Trolleybus wire switches
(called "frogs" in the UK) are
used where a trolleybus line
branches into two or where
two lines join. A switch may
be either in a "straight
Trolleybus wire switch (Type Soviet
through" or "turnout" position;
Union)
it normally remains in the
"straight through" position
unless it has been triggered, and reverts to it after a few seconds or
after the pole shoe passes through and strikes a release lever (in
Boston, the resting or "default" position is the "leftmost" position).
Triggering is typically accomplished by a pair of contacts, one on A switch in parallel overhead
each wire close to and before the switch assembly, which power a pair lines[42]
of electromagnets, one in each frog with diverging wires ("frog"
generally refers to one fitting that guides one trolley wheel/shoe onto
a desired wire or across one wire. Occasionally, "frog" has been used to refer to the entire switch assembly).
Multiple branches may be handled by installing more than one switch assembly. For example, to provide
straight-through, left-turn or right-turn branches at an intersection, one switch is installed some distance from
the intersection to choose the wires over the left-turn lane, and another switch is mounted closer to or in the
intersection to choose between straight through and a right turn[43] (this would be the arrangement in
countries such as the United States, where traffic directionality is right-handed; in left-handed traffic
countries such as the United Kingdom and New Zealand, the first switch (before the intersection) would be
used to access the right-turn lanes, and the second switch (usually in the intersection) would be for the left-
turn).

Three common types of switches[43] exist: power-on/power-off (the picture of a switch above is of this type),
Selectric, and Fahslabend.

A power-on/power-off switch is triggered if the trolleybus is drawing considerable power from the overhead
wires, usually by accelerating, at the moment the poles pass over the contacts (the contacts are lined up on
the wires in this case). If the trolleybus "coasts" through the switch, the switch will not activate. Some
trolleybuses, such as those in Philadelphia and Vancouver, have a manual "power-coast" toggle switch that
turns the power on or off. This allows a switch to be triggered in situations that would otherwise be
impossible, such as activating a switch while braking or accelerating through a switch without activating it.
One variation of the toggle switch will simulate accelerating by causing a larger power draw (through a
resistance grid), but will not simulate coasting and prevent activation of the switch by cutting the power.

A Selectric[44] switch has a similar design, but the contacts on the wires are skewed, often at a 45-degree
angle, rather than being lined up. This skew means that a trolleybus going straight through will not trigger
the switch, but a trolleybus making a turn will have its poles match the contacts in a matching skew (with
one pole shoe ahead of the other), which will trigger the switch regardless of power draw (accelerating
versus coasting).

For a Fahslabend switch, the trolleybus' turn indicator control (or a separate driver-controlled switch) causes
a coded radio signal to be sent from a transmitter, often attached to a trolley pole. The receiver is attached to
the switch and causes it to trigger if the correct code is received. This has the advantage that the driver does
not need to be accelerating the bus (as with a power-on/power-off switch) or trying to make a sharp turn (as
with a Selectric switch).

Trailing switches (where two sets of wires merge) do not require action by the operator. The frog runners are
pushed into the desired position by the trolley shoe, or the frog is shaped so the shoe is guided onto the exit
wire without any moving parts.

Manufacturing
Well over 200 different trolleybus makers have existed – mostly commercial manufacturers, but in some
cases (particularly in communist countries), built by the publicly owned operating companies or
authorities.[5]: 91–125 Of the defunct or former trolleybus manufacturers, the largest producers in North
America and Western Europe – ones whose production totalled more than 1,000 units each – included the
U.S. companies Brill (approx. 3,250 total), Pullman-Standard (2,007), and Marmon-Herrington (1,624); the
English companies AEC (approx. 1,750), British United Traction (BUT) (1,573), Leyland (1,420) and
Sunbeam (1,379); France's Vétra (more than 1,750); and the Italian builders Alfa Romeo (2,044) and Fiat
(approx. 1,700).[5] The largest former trolleybus manufacture is
Trolza (formerly Uritsky, or ZiU) since 1951, until they declared their
bankruptcy in 2017, building over 65000 trolleybuses. Also, Canadian
Car and Foundry built 1,114 trolleybuses based on designs by Brill.[5]

As of the 2010s, at least 30 trolleybus manufacturers exist. They

include companies that have been building trolleybuses for several
A ZiU-9 trolleybus in service in
decades, such as Škoda since 1936 and New Flyer, among others,
Piraeus, Greece, on the large
along with several younger companies. Current trolleybus Athens-area trolleybus system. The
manufacturers in western and central Europe include Solaris, Van Russian-built ZiU-9 (also known as
Hool, and Hess, among others. In Russia ZiU/Trolza has historically the ZiU-682), introduced in 1972, is
been the world's largest trolleybus manufacturer, producing over the most numerous trolleybus model
65,000 since 1951, mostly for Russia/CIS countries, but after its in history, with more than 45,000
bankruptcy, its facilities were partially loaned out to PC Transport built.[5]: 114 In the 2000s it was
effectively rendered obsolete by
Systems. Škoda is Western and Central Europe's largest and the
low-floor designs.
second largest in the world, having produced over 14,000 trolleybuses
since 1936, mostly for export, and it also supplies trolleybus electrical
equipment for other bus builders such as Solaris, SOR and Breda. In Mexico, trolleybus production ended
when MASA, which had built more than 860 trolleybuses since 1979, was acquired in 1998 by Volvo.
However, Dina, which is now that country's largest bus and truck manufacturer, began building trolleybuses
in 2013.[45]: 134

Transition to low-floor designs

A significant change to trolleybus designs starting in the early 1990s was the introduction of low-floor
models, which began only a few years after the first such models were introduced for motorbuses. These
have gradually replaced high-floor designs, and by 2012, every existing trolleybus system in Western Europe
had purchased low-floor trolleybuses, with the La Spezia (Italy) system being the last one to do so,[46] and
several systems in other parts of the world have purchased low-floor vehicles.

In the United States, some transit agencies had already begun to accommodate persons in wheelchairs by
purchasing buses with wheelchair lifts, and early examples of fleets of lift-equipped trolleybuses included
109 AM General trolleybuses built for the Seattle trolleybus system in 1979 and the retrofitting of lifts in
1983 to 64 Flyer E800s in the Dayton system's fleet.[47]: 61 The Americans with Disabilities Act of 1990
required that all new transit vehicles placed into service after 1 July 1993 be accessible to such
passengers.[48]

Trolleybuses in other countries also began to introduce better access for the disabled in the 1990s, when the
first two low-floor trolleybus models were introduced in Europe, both built in 1991, a "Swisstrolley"
demonstrator built by Switzerland's NAW/Hess and an N6020 demonstrator built by Neoplan.[49][50] The
first production-series low-floor trolleybuses were built in 1992: 13 by NAW for the Geneva system and 10
Gräf & Stift for the Innsbruck system. By 1995, such vehicles were also being made by several other
European manufacturers, including Skoda, Breda, Ikarus, and Van Hool.[51] The first Solaris "Trollino" made
its debut in early 2001.[52]: 30 In the former Soviet Union countries, Belarus' Belkommunmash built its first
low-floor trolleybus (model AKSM-333) in 1999,[53] and other manufacturers in the former Soviet countries
joined the trend in the early 2000s.
However, because the lifespan of a trolleybus is typically longer than
that of a motorbus, the budget allocation and purchase typically
factored in the longevity; the introduction of low-floor vehicles
applied pressures on operators to retire high-floor trolleybuses that
were only a few years old and replace them with low-floor
trolleybuses.[54] Responses varied, with some systems keeping their
high-floor fleets, and others retiring them early but, in many
instances, selling them second-hand for continued use in countries One of the NAW/Hess articulated
where there was a demand for low-cost second-hand trolleybuses, in trolleybuses delivered to Geneva in
particular in Romania and Bulgaria. The Lausanne system dealt with 1992, which were among the first
this dilemma in the 1990s by purchasing new low-floor passenger production-series low-floor
trailers to be towed by its high-floor trolleybuses,[54] a choice later trolleybuses
also made by Lucerne.

Outside Europe, 14 vehicles built by, and for, the Shanghai trolleybus
system in mid-1999 were the first reported low-floor trolleybuses in
Southeast Asia.[55] Wellington, New Zealand, took delivery of its first
low-floor trolleybus in March 2003,[56] and by the end of 2009 had
renewed its entire fleet with such vehicles.[57] Unlike Europe, where
low floor means "100%" low floor from front to back, most "low
floor" buses on other continents are actually only low-entry or part-
low floor. The Vancouver trolleybus system
completed the transition to an
In the Americas, the first low-floor trolleybus was a Busscar vehicle exclusively low-floor fleet in 2009.
supplied to the São Paulo EMTU system in 2001.[58] In North
America, wheelchair lifts were again chosen[54] for disabled access in
new trolleybuses delivered to San Francisco in 1992–94, to Dayton in 1996–1999, and to Seattle in 2001–
2002, but the first low-floor trolleybus was built in 2003, with the first of 28 Neoplan vehicles for the Boston
system.[58] Subsequently, the Vancouver system and the Philadelphia system have converted entirely to low-
floor vehicles, and in 2013 the Seattle and Dayton systems both placed orders for their first low-floor
trolleybuses. Outside São Paulo, almost all trolleybuses currently in service in Latin America are high-floor
models built before 2000. However, in 2013, the first domestically manufactured low-floor trolleybuses were
introduced in both Argentina and Mexico.[45]: 134

With regard to non-passenger aspects of vehicle design, the transition from high-floor to low-floor has meant
that some equipment previously placed under the floor has been moved to the roof.[48] Some transit operators
have needed to modify their maintenance facilities to accommodate this change, a one-time expense.

Double-decker trolleybuses
Since the end of 1997, no double-decker trolleybuses have been in service anywhere in the world, but, in the
past, several manufacturers made such vehicles. Most builders of double-deck trolleybuses were in the
United Kingdom, but there were a few, usually solitary, instances of such trolleybuses being built in other
countries, including in Germany by Henschel (for Hamburg); in Italy, by Lancia (for Porto, Portugal); in
Russia, by the Yaroslavl motor plant (for Moscow) and in Spain, by Maquitrans (for Barcelona).[5] British
manufacturers of double-deck trolleybuses included AEC, BUT, Crossley, Guy, Leyland, Karrier, Sunbeam
and others.[5]
In 2001, Citybus (Hong Kong) converted a Dennis Dragon (#701)
into a double-decker trolleybus,[59] and it was tested on a 300-metre
track in Wong Chuk Hang in that year.[59] Hong Kong decided not to
build a trolleybus system, and the testing of this prototype did not
lead to any further production of vehicles.

Use and preservation

A trolleybus in Bradford in 1970. The
There are currently 300 cities or metropolitan areas where Bradford Trolleybus system was the
last one to operate in the United
trolleybuses are operated,[4] and more than 500 additional trolleybus
Kingdom; closing in 1972.
systems have existed in the past.[5] For an overview, by country, see
Trolleybus usage by country, and for complete lists of trolleybus
systems by location, with dates of opening and (where applicable)
closure, see List of trolleybus systems and the related lists indexed
there.

Of the systems existing as of 2012, the majority are located in Europe

and Asia, including 85 in Russia and 43 in Ukraine.[4] However, there
are eight systems existing in North America and nine in South
Monument to Crimean Trolleybus
America.[4]

Trolleybuses have been preserved in most of the countries where they have operated. The United Kingdom
has the largest number of preserved trolleybuses with more than 110, while the United States has around
70.[5] Most preserved vehicles are on static display only, but a few museums are equipped with a trolleybus
line, allowing trolleybuses to operate for visitors. Museums with operational trolleybus routes include three
in the UK – the Trolleybus Museum at Sandtoft, the East Anglia Transport Museum, and the Black Country
Living Museum – and three in the United States – the Illinois Railway Museum, the Seashore Trolley
Museum, and the Shore Line Trolley Museum[60] – but operation of trolleybuses does not necessarily occur
on a regular schedule of dates at these museums.

See also
Battery electric bus
Bus rapid transit
Dual-mode bus
Electric bus
Electric vehicle battery
Electromote
Guided bus
Gyrobus
List of trolleybus manufacturers
List of trolleybus systems
Parallel overhead lines
Traction substation
Trolleytruck

Notes
1. Joyce, J.; King, J. S.; and Newman, A. G. (1986). British Trolleybus Systems, pp. 9, 12.
London: Ian Allan Publishing. ISBN 0-7110-1647-X.
2. Dunbar, Charles S. (1967). Buses, Trolleys & Trams. Paul Hamlyn Ltd. (UK). Republished 2004
with ISBN 0-7537-0970-8 or 9780753709702.
3. "Trolley service begins the next 60 years" (https://web.archive.org/web/20140201213805/http://
www.translink.ca/en/About-TransLink/Media/2008/August/Trolley-service-begins-the-next-60-ye
ars.aspx) (Press release). Vancouver: TransLink. 16 August 2008. Archived from the original (ht
tp://www.translink.ca/en/About-TransLink/Media/2008/August/Trolley-service-begins-the-next-6
0-years.aspx) on 1 February 2014. Retrieved 6 September 2012.
4. Webb, Mary (ed.) (2012). Jane's Urban Transport Systems 2012–2013, pp. "[23]" and "[24]" (in
foreword). Coulsdon, Surrey (UK): Jane's Information Group. ISBN 978-0-7106-2994-4.
5. Murray, Alan (2000). World Trolleybus Encyclopaedia. Yateley, Hampshire, UK: Trolleybooks.
ISBN 0-904235-18-1.
6. Elektromote (https://www.siemens.com/history/en/innovations/transportation.htm#toc-2),
Siemens History website on 14 August 2015
7. Di̇ Kmen, İsmail Can; Eki̇ Ci̇ , Yunus Emre; Karadağ, Teoman; Abbasov, Teymuraz; Hamamci,
Serdar Ethem (30 January 2021). "Electrification in Urban Transport: A Case Study with Real-
time Data" (https://doi.org/10.17694%2Fbajece.837248). Balkan Journal of Electrical and
Computer Engineering. 9 (1): 69–77. doi:10.17694/bajece.837248 (https://doi.org/10.17694%2
Fbajece.837248). ISSN 2147-284X (https://search.worldcat.org/issn/2147-284X).
8. Ashley Bruce, Lombard-Gerin and Inventing the Trolleybus (Trolleybooks, 2017, ISBN 978-0-
904235-25-8), p. 88 et seq.
9. Charles S. Dunbar, Buses, Trolleys and Trams (Paul Hamlyn Ltd, 1967, no ISBN), p. 81 et seq.
10. Henry Martin, Lignes Aeriennes et Trolleys pour Automobile sur Route (Libraire Polytechnique
Ch., 1902, no ISBN), p. 29 et seq.
11. Dunbar p. 84
12. Dunbar p. 83
13. J. S. King, Keighley Corporation Transport, (Advertiser Press Ltd, 1964, no ISBN) p. 39 et seq.
14. Dunbar, p. 90
15. "Plan for city trolleybus comeback" (http://news.bbc.co.uk/2/hi/uk_news/england/west_yorkshir
e/6755469.stm). BBC News. 15 June 2007. Retrieved 3 June 2009.
16. "Trolley with an internal combustion engine. Electric cars of the USSR. Excerpt of a Cargo
Trolley Bus" (https://gtshina.ru/en/uluchsheniya-v-salone/trolleibus-s-dvigatelem-vnutrennego-s
goraniya-elektromobili-sssr/). gtshina.ru. Retrieved 20 October 2020.
17. "Transport in Kiev, Ukraine" (https://www.classicbuses.co.uk/kiev.html).
www.classicbuses.co.uk. Retrieved 20 October 2020.
18. Trolleybus Magazine No. 321 (May–June 2015), p. 90.
19. "Marrakech trolleybus route inaugurated" (https://www.railwaygazette.com/projects-and-plannin
g/marrakech-trolleybus-route-inaugurated/45245.article). Metro Report International. Railway
Gazette International. Archived (https://web.archive.org/web/20200619234203/https://www.rail
waygazette.com/projects-and-planning/marrakech-trolleybus-route-inaugurated/45245.article)
from the original on 19 June 2020.
20. "北京多措并举治理PM2.5 一微克一微克往下抠-新华网" (https://web.archive.org/web/20200116
183217/http://www.xinhuanet.com/local/2020-01/15/c_1125462807.htm). www.xinhuanet.com.
Archived from the original (http://www.xinhuanet.com/local/2020-01/15/c_1125462807.htm) on
16 January 2020. Retrieved 14 March 2020.
21. "PyongyangTimes | home" (http://www.pyongyangtimes.com.kp/?bbs=34493).
www.pyongyangtimes.com.kp. Retrieved 2 September 2021.
22. "Trolleybuses Are Back to Prague After 50 Years" (https://www.praguemorning.cz/trolleybuses-
are-back-to-prague-after-50-years/). 15 October 2022.
23. Neumann, Peter (23 January 2023). "Aus für die Strippe: Durch Berlin werden keine O-Busse
mehr fahren" (https://www.berliner-zeitung.de/mensch-metropole/verkehr-senat-bvg-projekt-ob
erleitungsbus-in-aller-stille-beerdigt-aus-fuer-die-strippe-durch-berlin-werden-keine-o-busse-me
hr-fahren-li.310007) [End of the wire: There won't be trolleybuses going through Berlin].
Berliner Zeitung (in German). Berlin. Retrieved 30 July 2023.
24. "Power in downtown Vancouver won't be fully restored until Tuesday" (http://www.cbc.ca/news/
canada/british-columbia/power-in-downtown-vancouver-won-t-be-fully-restored-until-tuesday-1.
739479). CBC News. 14 July 2008. Other reports stated that the (electrical) explosion did not
affect power supply to the trolleybuses (only implied by this article).
25. Ashley Bruce. "Overhead" (http://www.tbus.org.uk/overhead.htm). Tbus.org.uk. Retrieved
29 November 2010.
26. "沈阳1999年"电改汽"的真正原因_沈阳公交网" (http://www.shenyangbus.com/a/gjls/2010/0614/
255.html). www.shenyangbus.com. Retrieved 2 September 2021.
27. "Electric Trolley Bus Fact Sheet" (https://web.archive.org/web/20170217035300/http://www.sea
ttle.gov/transportation/docs/ElectricTrolleyBusFactSheet0110.pdf) (PDF). Seattle Department
of Transportation. Archived from the original (http://www.seattle.gov/transportation/docs/Electric
TrolleyBusFactSheet0110.pdf) (PDF) on 17 February 2017. Retrieved 29 March 2012.
28. Trolleybus Magazine No. 267 (May–June 2006), p. 71. National Trolleybus Assn. (UK).
29. Koch, John (28 October 2016). "Farewell to Metro's Breda trolleys" (https://kingcountymetro.blo
g/2016/10/28/farewell-to-metros-breda-trolleys/). Metro Matters Blog. Retrieved 26 January
2023.
30. "NETransit: MBTA Vehicle Inventory Main Page" (http://www.transithistory.org/roster/).
roster.transithistory.org. Retrieved 17 January 2024.
31. "上海无轨电车"复兴":全换成新型辫子车 车辆增加两倍-无轨电车 辫子 高油价时代 混搭 上海公
交-上海频道-东方网" (http://sh.eastday.com/m/20140626/u1a8178158.html). sh.eastday.com (in
Chinese). Retrieved 6 June 2020.
32. Martin Harák (13 October 2019). "Hybrid trolleybuses in the Czech Republic" (https://www.urba
n-transport-magazine.com/en/hybrid-trolleybuses-in-the-czech-republic/). Urban Transport
Magazine.
33. Wong, Marcus (5 February 2019). "Battery powered trolleybuses in Beijing" (https://www.check
erboardhill.com/2019/02/battery-powered-trolleybuses-in-beijing/). Checkerboard Hill. Retrieved
6 June 2020.
34. Mario (11 May 2020). "Yutong: the Chinese leader on worldwide expansion (as electric buses
gain ground)" (https://www.sustainable-bus.com/news/yutong-bus-zhengzhou-electric-bus/).
Sustainable Bus. Retrieved 6 June 2020.
35. "THE INNOVATIVE TROLLEYBUS: IN MOTION CHARGING IN NEW KNOWLEDGE BRIEF"
(https://www.uitp.org/news/innovative-trolleybus-motion-charging-new-knowledge-brief).
36. T, Tom (25 September 2020). "De nye Solaris trolleybussene er kommet til Bergen" (https://bus
smagasinet.no/de-nye-solaris-trolleybussene-er-kommet-til-bergen/). Bussmagasinet (in
Norwegian Bokmål). Retrieved 6 December 2021.
37. "我市第一批双源无轨电车来啦十大亮点抢先看" (https://mp.weixin.qq.com/s/Db2e3UKcIqDAlvi0
fOrxEQ) (in Chinese).
38. "BVG Berlin plans implementation of hybrid trolleybuses" (https://www.urban-transport-magazin
e.com/en/bvg-berlin-plans-implementation-of-hybrid-trolleybuses/). Urban Transport Magazine.
3 March 2020.
39. "How in motion charging trolleybuses are advancing our cities: Explore the Knowledge Brief" (h
ttps://www.uitp.org/news/trolleybus-in-motion-charging-knowledge-brief/). Retrieved
18 December 2023.
40. "IMC500 / e-Bus with In Motion Charging (IMC®)" (https://kiepe.knorr-bremse.com/en/de/buses
-and-e-mobilty/e-systems/imc500-e-bus-with-in-motion-charging-imc/). Retrieved 27 September
2024.
41. "Ask an Expert: Trolly bus" (https://www.sciencebuddies.org/science-fair-projects/ask-an-exper
t/viewtopic.php?t=15598). www.sciencebuddies.org. Retrieved 13 October 2023.
42. G. Cebrat. "Greenfleet" (https://web.archive.org/web/20060212203153/http://www.greenfleet.inf
o/). Greenfleet.info. Archived from the original (http://www.greenfleet.info) on 12 February 2006.
Retrieved 29 November 2010.
43. "Electric Vehicle Technologies" (https://web.archive.org/web/20060303075510/http://www.vcn.b
c.ca/t2000bc/learning/etb/electric_vehicles.html). Transport 2000 BC. Archived from the original
(http://www.vcn.bc.ca/t2000bc/learning/etb/electric_vehicles.html) on 3 March 2006.
44. Trademark of Ohio Brass Co., maker of trolley wire fittings and equipment and trolley poles.
The typewriter from IBM bearing that name had not been invented yet.
45. Trolleybus Magazine No. 311 (September–October 2013).
46. Trolleybus Magazine No. 305 (September–October 2012), p. 119.
47. DeArmond, R. C. (May–June 1985). "The Trolleybus System of Dayton, part 2". Trolleybus
Magazine No. 141, pp. 49–64.
48. "Getting on board" (July–August 1993). Trolleybus Magazine No. 190, pp. 86–87. National
Trolleybus Association (UK).
49. Trolleybus Magazine No. 179 (September–October 1991), pp. 100–101.
50. "The Neoplan N6020 Low-Floor Trolleybus". Trolleybus Magazine No. 183 (May–June 1992), p.
68.
51. Braddock, Andrew (March–April 1995). "Low-floor Trolleybuses – Making Access Easier".
Trolleybus Magazine No. 200, pp. 30–37.
52. Turzanski, Bohdan (March–April 2012). "Trollino 500, Part 1". Trolleybus Magazine No. 302, pp.
28–35.
53. Trolleybus Magazine No. 226 (July–August 1999), p. 89.
54. "Low-floor or Long Life?" (November–December 1998). Trolleybus Magazine No. 222, p. 122.
National Trolleybus Association (UK).
55. Trolleybus Magazine No. 230 (March–April 2000), p. 39.
56. Trolleybus Magazine No. 249 (May–June 2003), p. 39.
57. Bramley, Rod (November–December 2012). "New Zealand: A 'Roller Coaster' Ride, Part 4".
Trolleybus Magazine No. 306, pp. 126–134.
58. Box, Roland (July–August 2010). "More about the 2000s". Trolleybus Magazine No. 292, pp.
78–82. National Trolleybus Association (UK). ISSN 0266-7452 (https://www.worldcat.org/searc
h?fq=x0:jrnl&q=n2:0266-7452).
59. Trolleybus Magazine No. 238 (July–August 2001), pp. 73 and 88.
60. Isgar, Carl F. (January–February 2011). "Preservation Update". Trolleybus Magazine No. 295,
p. 11. National Trolleybus Association (UK). ISSN 0266-7452 (https://www.worldcat.org/search?
fq=x0:jrnl&q=n2:0266-7452).

Further reading
Bruce, Ashley R. Lombard-Gerin and Inventing the Trolleybus. (2017) Trolleybooks (UK).
ISBN 978-0-904235-25-8
Cheape, Charles W. Moving the masses: urban public transit in New York, Boston, and
Philadelphia, 1880-1912 (Harvard University Press, 1980)
Dunbar, Charles S. (1967). Buses, Trolleys & Trams. Paul Hamlyn Ltd. (UK) [republished 2004
with ISBN 0-7537-0970-8 or 9780753709702]
McKay, John P. Tramways and Trolleys: The Rise of Urban Mass Transport in Europe (1976)
Murray, Alan (2000). World Trolleybus Encyclopaedia. Trolleybooks (UK). ISBN 0-904235-18-1
Porter, Harry; and Worris, Stanley F.X. (1979). Trolleybus Bulletin No. 109: Databook II. North
American Trackless Trolley Association (defunct)
Sebree, Mac; and Ward, Paul (1973). Transit's Stepchild, The Trolley Coach (Interurbans
Special 58). Los Angeles: Interurbans. LCCN 73-84356
Sebree, Mac; and Ward, Paul (1974). The Trolley Coach in North America (Interurbans Special
59). Los Angeles: Interurbans. LCCN 74-20367

Periodicals
Trolleybus Magazine (ISSN 0266-7452 (https://www.worldcat.org/search?fq=x0:jrnl&q=n2:0266
-7452)). National Trolleybus Association (UK), bi-monthly
Trackless, Bradford Trolleybus Association, quarterly
Trolleybus, British Trolleybus Society (UK), monthly

External links
(in German) TrolleyMotion – an international action group to promote modern trolleybus
systems, and database of systems in the world (https://www.trolleymotion.eu)
British Trolleybuses (http://www.trolleybus.co.uk/)
Trolleybuses in Latin America (http://www.tramz.com)
North American trolleybus pictures (http://www.trolleybuses.net/index.htm)
Trolleybuses in Europe (https://public-transport.net/index_trolley.htm)
Urban Electric Transit - Database/Photo gallery (https://transphoto.org)

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