Why are trams heavier for their size than buses?

[Myrtone]

So why are bus-sized rail vehicles heavier than buses? Why, for example are B class trams heavier than articulated buses? Is is true that the sprung weight of a tram is greater than that of a bus?

[boronia]

Bus weights (inc passenger capacity) are constrained by wheel/axle loads imposed on roads. Trams have higher axle load capabilities, and can thus be built to carry much higher passenger densities.

[Myrtone]

How are trams built to carry more people than buses of the same size?

[Myrtone]

I still have not got an answer. Does no one here have the specific information I am after. I understand that buses are road vehicles and trams are rail vehicles and that the mechanics of a rail vehicle are quite different from that of a road vehicle but I grew up think of a tram as like a bus that aside. After all, I grew up with bus-sized trams that are used like buses, making me think of them as buses on rails.

It turns out that a Z3 class tram weighs around 21.8 tonnes. Does anyone here know how that compares with the MAN SL200? That is a bus from the same era that is also not articulated.

[boronia]

A 2 axle bus would have a maximum loaded weight of 15 tonnes. Deduct the weight of passenger capacity from that.

[Myrtone]

Does "maximum loaded weight" mean gross vehicle mass, something rail vehicles do not have.

[boronia]

Rail vehicles do have an effective GVM, which is expressed in terms of "axles loads".

Axle loads are constrained by the quality of the rail and supporting sub-structures.

[Myrtone]

But the maximum loaded weight of a twin bogie tram is greater than that of a bus of similar size. It is as if limiting a vehicle to fixed tracks somehow increases the maximum loaded weight.

[Myrtone]

A 2 axle bus would have a maximum loaded weight of 15 tonnes. Deduct the weight of passenger capacity from that.

But I would need to know the unladen weight of the bus as well as the maximum loaded weight to deduce the weight of passenger capacity, wouldn't I?

[eddy]

I suppose you could say around 80 kg https://www.google.com/search?q=average ... UTF-8#ip=1
Assuming the electric Trailerbus axle weights are 6t + 9t + 20t less prime 10t + 10t trailer + 1,000 km batteries @ 3t + 150 passengers @ 80kg passengers.
Hope this helps mate.

[Myrtone]

Hard to say if it helps because it confuses me.

[eddy]

Hard to say if it helps because it confuses me.

As Boronia says find the specifications of whatever bus empty weight is and allow 80 kg per passenger and although buses can more than the legal axle weight it is best to think 6t on single tyres and 9t on duels on a standard bus.

General mass and dimensions from NHVR https://www.nhvr.gov.au/files/201801-07 ... art-a3.pdf will help you.

[boronia]

A 2 axle bus would have a maximum loaded weight of 15 tonnes. Deduct the weight of passenger capacity from that.

But I would need to know the unladen weight of the bus as well as the maximum loaded weight to deduce the weight of passenger capacity, wouldn't I?

Yes, you would.

[Myrtone]

General mass and dimensions from NHVR

I looked at that page but I could find the total vehicle mass limit but not what the empty weight is.

[eddy]

General mass and dimensions from NHVR

I looked at that page but I could find the total vehicle mass limit but not what the empty weight is.

Google the specifications on whatever bus you are interested and I have used the Mercedes as an example where the empty weight is 13400 kilograms and the rated weight is 18000 kilograms.
https://www.mercedes-benz-bus.com/en_AM ... -data.html
Although most buses are allowed more than the legal weight and they want to go even more with electric buses coupled with the extra weight and low profile tyres of cars you can expect more potholes next time it rains.

[Myrtone]

That really raises the question of why not reintroduce trolleybuses, for example to Hobart and Launceston.

[eddy]

That really raises the question of why not reintroduce trolleybuses, for example to Hobart and Launceston.

They cannot replace the XPT

[Myrtone]

How did X.P.T come into it?

[Linto63]

That really raises the question of why not reintroduce trolleybuses, for example to Hobart and Launceston.

For the exact same reasons given in that thread five years ago, nothing has changed.

[Myrtone]

The thing is that bigger batteries are a weight penalty.

[eddy]

The thing is that bigger batteries are a weight penalty.

There are horses for coarses and there is nothing wrong with trolly buses exept they cannot go long distances so around town OK as they do not get stuck behind each other and bikes do not get stuck in dangerous tram lines but if you need to go 1,000 kilometers to replace the XPT you need to have 3t of batteries with more wheels as charging every 300 km will not cut it.

[boronia]

The thing is that bigger batteries are a weight penalty.

There are horses for coarses and there is nothing wrong with trolly buses exept they cannot go long distances so around town OK as they do not get stuck behind each other and bikes do not get stuck in dangerous tram lines but if you need to go 1,000 kilometers to replace the XPT you need to have 3t of batteries with more wheels as charging every 300 km will not cut it.

Two intermediate stops for driver breaks, passenger refreshments and rapid battery recharge.

[Myrtone]

In-motion charging may be preferable to treating batteries like fuel tanks. Modern trolleybuses all have auxiliary batteries and are capable of limited off-wire manoeuvres. These batteries charge while under wires, moving or stationary.
Plenty of new trolleybuses are still being made for overseas systems and in fact, they are making a comeback in Prague.

[eddy]

There are horses for coarses and there is nothing wrong with trolly buses exept they cannot go long distances so around town OK as they do not get stuck behind each other and bikes do not get stuck in dangerous tram lines but if you need to go 1,000 kilometers to replace the XPT you need to have 3t of batteries with more wheels as charging every 300 km will not cut it.

Two intermediate stops for driver breaks, passenger refreshments and rapid battery recharge.

I saw them try that in America but half the chargers did not work or people just disconnected it if they did not watch it.

But Australia may be very different mate.

Ps
A semitrailer would not even notice an extra 2t of batteries compared to the hassle of charging.

https://www.youtube.com/watch?v=RtOStuAOoQo

[1whoknows]

Perhaps the two of you can unite and present the world with the trailer trolleybus?