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Trams emit no fumes whatever.
Why are fumes so
bad for Bath ?
What
are the pollution levels in Bath?
How do trams rate for Sustainability?
Compared with all other forms of public transport, trams have
very little effect on the environment.
The information on this page is, therefore, mostly concerned with
what trams do NOT do.
Trams emit no fumes whatever, they have no smell and leave no residue except the minutest amounts of harmless metal dust from the track and wheels and occasional traces of ozone from sparking.
Tyres
The tyres are made of steel
and will last a very long time. Each time they become worn, they
are machined back to shape and continue in use until finally worn-out
after many hundreds of thousands of miles.
Worn-out tyres are re-melted as valuable scrap and recycled in
their entirety.
Lubricants
Trams use similar lubricants to all other vehicles
in some of their transmission parts, but, because the running
temperatures and stresses are lower, they may not need changing
as often.
Trams do not use a gearbox for changing speed, so there are no
waste lubricants from that source.
Trams do not have an engine and so do not require regular engine
oil changes in the way combustion-engined vehicles do.
Track
A lightweight tram track of the type proposed for Bath, occupies a width of less than 2 metres. The amount of construction work is minimal and it can run along existing roads, in the grass central reservation of dual carriageways, through pedestrian areas and in narrow streets unsuitable for buses.
The modern polyurethane-coated rail can be made to blend with a tarmac road surface so as to be hardly noticeable.
Wires
The overhead wire on modern tramways can be lightweight and unobtrusive. In open areas it is easily ignored and against buildings it will hardly show at all. More on overhead wires?
Trams have a lifetime of 30 years at least,
sometimes 50 or more with major refits. The environmental costs
of such a long-lived vehicle are trivial compared with combustion-engined
vehicles which need frequent replacement and employ scarce resources
for catalysts and special highly-stressed alloys.
Trams have no engine or gearbox, both of which are highly complex
items to manufacture and replace. Their electric motors normally
have only two bearings, which should have a life of over 10 years,
and a pair of carbon brushes which require regular replacement
but present no environmental hazard.
More about vehicle technology?
Trams are very quiet indeed when running and virtually silent when stopped, a fact which has been cited as a safety problem. It is, however, much easier to make a quiet tram noisy when required, than to make a noisy bus quiet.
Modern resilient track structure and tram wheels are particularly effective at preventing the rumbling noise which used to characterise trams. There is, however, still a small amount of wheel squeal when rounding tight curves but the use of a differential gear in the axle of modern trams minimises this and the grinding effects which used to cause severe track wear.
The greatest source of noise on Sheffield and Wolverhampton trams is the blowers which cool the control equipment and/or ventilate the interior of the vehicle. Although these seem noisy at the termini, when the vehicle is parked in an ordinary street the sound becomes inaudible. Might the blowers have to be redesigned if trams help to empty our streets of cars and make them quiet once more?
All forms of transport use energy, in the case of trams, the total energy budget, measured in CO2 production, is lower than any comparable combustion-engined vehicle.
A tramway cannot be run directly off a single
sustainable energy source because it needs surges
of power which make such operation uneconomical.
There are ways of using sustainable energy
in a tram provided these surges can be met in other ways.
Trams have the ability to save power by regenerating, that is, returning energy to the power supply when braking. This is particularly valuable in hilly districts such as Bath; and even in Manchester it resulted in savings of over 20% of the electrical consumption.
The tramway system planned for Bath would only cross the frontage of one historical building in the centre of Bath (The Mineral Water Hospital in Upper Borough Walls). The visual effect of the track and wires would be negligible.
Overall, the appearance of a well-planned tramway is infinitely preferable to a city clogged with cars and buses and cluttered with all the street furniture these necessitate.