What is the advantage / reason for many trams being high floored and non-accessible?
In the last few weeks, I've taken a lot more trams than I normally do, in a few different countries. Some of those trams have had low floors, allowing me to just step on / step on wheeling some luggage. Others have involved climbing up several steps to get in, often struggling with luggage.
The low floor accessible trams haven't only been handy for me when I've had luggage, they've also looked nice and easy for families with prams / pushchairs, wheelchair uses, old people with mobility problems etc. I've spotted very few people in those categories struggling their way onto the high floor trams, and the surprised looks I've tended to get hauling my suitcases up into them seems to indicate that most people don't even try...
I'm guessing that people buying trams don't just go "I know, let's buy a tram that isn't accessible just for fun", and there must be a good reason why many trams out there are high floored and non-accessible. What is it?
Best Answer
From an engineering point of view, a tram is a vehicle that takes electricity from somewhere (overhead wires or third rail underneath), use motors to convert this into torque, and spins wheels to move the tram. The obvious solution is put all this machinery at ground level, right next to the wheels, and put the passengers on top. Ta-dah, a high-floor tram.
If, on the other hand, you want a low-floor tram, you've got to figure out some way to hide this machinery somewhere else, so passengers can use the space near the ground, but still feed the power to the wheels. This is tricky and expensive, plus the tram can get top-heavy and unstable if you stack everything on top. One mitigation is to fix some of the wheels in place, so they require less space, but then the turning radius of the tram also becomes larger, because the wheels can't turn sideways.
That said, this is largely considered a solved problem these days, so virtually all new trams are low-floor. However, trams are expensive and last decades, so replacing old rolling stock takes a good long time. And if you've attacked the problem from a different angle and built elevated stops to make high-floor trams accessible, the same high stop is no longer compatible with low-floor trams!
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What is high floor LRT?
High-Floor LRT They are characterized by high-floor rolling stock that requires specialized platforms for the loading and unloading of passengers. These lines require greater infrastructural investments (e.g. complete stations) than streetcars or low-floor LRT lines.Is tram a train?
Trams, which are also known as trolley cars, are much shorter and lighted in comparison. Travelling much slower than trains (in respect for the vehicular traffic around them) trams are powered by an overhead electrical apparatus or occasionally by diesel.What is low-floor train?
A low-floor tram is a tram that has no stairsteps between one or more entrances and part or all of the passenger cabin. The low-floor design improves the accessibility of the tram for the public, and also may provide larger windows and more airspace.The Potential Benefits of Medical Marijuana | Dr. Alan Shackelford | TEDxCincinnati
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Answer 2
Cost, and speed.
Some public transport companies report that low floor trams have 15% higher maintenance costs for the rolling stock, and 20% higher maintenance costs for the infrastructure on average (source in German).
The low-floor designs typically also decrease the speed at which a tram can drive through a curve (usually 4–15 km/h in 20 m radius curve)
There's also quite a good article on Wiki about Low-floor trams.
Answer 3
The general answer is, because rail-borne rolling stock is expensive, it is only rational to expect trams to have a long life cycle. It is not unusual to see trams which are 30 years old, and in some places you can meet trams built in something like the 1930s and still in use.
Thus, because low-floor tram designs are relatively new (introduced in 1980s and only ripened in 2000s), the share of high-floor trams must necessarily be sufficiently high still, even in the most advanced cities.
However, some tramway systems have features that make it impossible to use low-floor cars. For example, San Francisco's Muni Metro or Düsseldorf's Stadbahn have underground stretches where stations have high platforms. Unless those stations are rebuilt (which may be prohibitively expensive), they are bound to use high-floor cars.
There may also be less obvious reasons to use high-floor trams.
We might go into further specific details if you tell us about which particular cities made you ask your question.
Update:
The particular cities named were Budapest and Melbourne.
Both cities have very extensive tram networks (Melbourne's is the largest in the world). Their fleets are numbered in hundreds of cars and can only be replaced gradually.
Budapest, as far as I know, has not been showing a quick progress in this matter because most of their money went into the construction of a new metro line.
There are no special features impeding the use of low-floor trams that I ever heard of.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
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