But while it's comforting to know you could walk right across the
city, few people are going to want to do it often. That's where
the trolleybuses come in.
Trolleybus Network
The district centres of Cloverleaf City are linked by a network of
efficient, non-polluting trolleybuses.
They operate at 2 to 3
minute intervals throughout the day, providing quick and easy transport around
the city. Even in the middle of the night, you would never have to wait more
than 12 minutes.
They are fast. Trolleybuses accelerate quickly, and in
Cloverleaf City there's never any traffic for them to get stuck in or
red lights to wait at. Stops are spaced a good distance apart.
And with 5 doors dwell times are kept to a minimum.
And they are free to ride. When you factor in the costs of
smart cards, machines to read them, staff to enforce them and the delays
they cause, collecting fares is a significant expense in itself.
With everybody in the city using the trolleybus network, it would be
simpler and cheaper to cover operating costs through city taxes and
parking fees instead.
The trolleybuses are fitted with kerb guidance for level boarding at stops,
making them accessible to everyone.
They have regenerative brakes for greater energy efficiency, recovering
energy that would otherwise be lost when braking and feeding it back
into the overhead lines.
Auxiliary batteries enable them to operate away from the overhead lines
for short periods of time, allowing them to
bypass any obstacles. Batteries also eliminate the need for
pointwork and the wiring of maintenance and storage sheds, lowering
visual pollution and reducing costs.
And the trolleybuses are all double articulated, allowing each driver
to transport the maximum number of passengers.
Layout
Of course public transport of this quality cannot be justified
everywhere; it requires very high ridership (here coming from a dense city that
discourages car use) and a tight route layout.
With public transport there are basically
2 layouts:
Grid
Spoke (6)
The grid layout provides the quickest transportation. But its
much longer track length makes it 66% more expensive to build and
operate than the spoke layout. The frequent crossings would
require bridges or complex systems of points, and very little open space
is provided in between districts.
Spoke (8)
An 8 spoke layout requires about the same track
length per district as a 6 spoke layout, but provides
quicker transportation.
Districts
Track length
Crossings
Longest journey
Grid
36
60
16
10
Spoke (6)
37
36
0
12
Spoke (8)
42.5
42.33
0
10.4
Why the Trolleybus?
With experimental hydrogen fuel cell buses still inefficient and
underpowered, and subways and elevated rail too expensive for small
cities, there are 3 real options:
Trams
Pros:
Long vehicles require fewer drivers.
Vehicles can be connected together in trains for busy
periods.
Non-polluting.
Cons:
Still quite expensive.
Unable to drive around obstacles.
Overhead lines regarded as an eyesore.
Diesel Buses
Pros:
Cheapest option.
Also the most adaptable.
Cons:
Smelly, noxious exhaust is hazardous to human health.
Noisy.
Lurching ride.
Vibrations from the diesel engine.
Trolleybuses
Pros:
Non-polluting and quiet.
Much smoother ride than diesel buses.
Can leave overhead lines to bypass obstacles.
Cons:
Even double articulated, they can only seat around 90
passengers.
More expensive than diesel buses.
Overhead lines regarded as an eyesore.
The Verdict
Diesel buses, being almost as loud and smelly as the fifty or so cars
they replace, have by far the least chance of tempting people out of
their cars. Hybrid buses are better, using a combination of
diesel and electric, but still emit pollutants directly into the
street. This leaves trams and trolleybuses.
Both are non-polluting, taking their power from overhead
lines. Both are energy efficient, especially when equipped with regenerative
brakes, and offer smooth, quiet rides. In short, both are excellent modes of
public transportation, but which is best?
The biggest advantage trams have over trolleybuses is their
greater capacity, so each driver can transport more passengers and thus fewer
are needed, reducing operating costs. In practice, however, very long trams
don’t mix well with pedestrian areas. For example the Nottingham trams are 33m
long, compared to 25m for a double articulated bus.
Trams also benefit from level boarding. With the platform and vehicle
floor at the same height and only a narrow gap in between, they are accessible
to everyone. But buses can do this too.
Kerb guidance is the simplest means of achieving this. The bus is fitted with
small guide wheels down each side. These wheels push against raised kerbs at
stations, docking the bus automatically.
So trolleybuses can do more or
less anything trams can do, but what advantages do they offer?
Trolleybuses are cheaper than trams. Since they operate on
rubber tyres, they are quieter. They’re safer too, able to brake much more
quickly in an emergency and steer around stray pedestrians.
In any public transportation system, reliability is very
important. When an entire city depends upon that system, reliability is
absolutely crucial. And it is here where the trolleybus really scores over the
tram. If equipped with an auxiliary battery, the bus is free to leave the
overhead lines to circumvent obstacles, whether they be broken-down vehicles or
road works. Trams just can’t do this, and any such problems would have a large
impact on service.
With medium sized cities the higher capacity of trams makes
them more or less essential, but the best choice for small cities is the
trolleybus.
Train Station
A train station, located under the central bus station, provides transport into and out of the
city.
The train line runs into the city alongside the road network, as
close as possible to conserve green space, then plunges underground as
it reaches the city centre.
