Excavation Vacuum

[DerbyBorn]

I've seen several of the Utilities using a huge truck based vacuum cleaner to empty excavations. They look impressive but must cost a lot.

[Nightjar]

They have been using them around here to excavate for lamp posts. They have the advantage that, if you only need a small hole, you don't have to dig a big one, just to get access for the digger bucket and, unlike a borer, they remove their own spoil.

Colin Bignell

[Chris J Dixon]

They have used them a lot for work associated with Nottingham Tram lines 2 & 3. It enables them to expose services with much less risk of damage, thereby avoiding another significant potential cost.

Chris

[Tim Streater]

Why are people putting tram-lines in? Seems an expensive way of moving people about, given the infrastructure required. Woss wrong with trolley buses?

[John Williamson]

There's probably no subsidy for trolley buses. Anyway, trams are old enough to be the Next Big Thing (tm) in urban transport. When they find they don't work, they'll rip out all the tram tracks and replace them with dedicated bus lanes, until they work out that the real problem is actually too many people trying to get to work in the same place at the same time. Then the Powers That Be may start investing in infrastructure that means we move data instead of people and paper.

[DerbyBorn]

Trolley Buses should make a come back. The infrastructure costs are far less and the vehicles are cheaper. They are still manufactured by several companies so availability is not a factor.

A mix of dedicated lanes and public roads is suitable. Some can run off the wires on battery power if needed to divert.

I think the local politicians think that going for a tramway makes the city appear to be progressive! example:

[harryagain]

They have hunderds of miles of trolley wires/routes in Sao Paulo.

[meow2222]

How is a road with rails cheaper than a road? How is a bus with guided steering cheaper?

NT

[meow2222]

How is a road with rails cheaper than a road? How is a bus with guided steering cheaper?

NT

[Vir Campestris]

Well, in the case of the Cambridge guided busway - the guided way is exactly bus width. I'd be happy to drive a car down it, but it would require a lot of concentration to fit a vehicle exactly road sized along.

There are however people who prefix "guided" with "mis".

Andy

[gremlin_95]

FWIW, I used to use the Nottingham tram system to get to college before I could drive, it was always busy and very rarely did I encounter any problems. I much preferred it to the bus especially as it was linked to the railway station via a footbridge which made it quite simple to connect.

[Tim+]

You do know that trolley buses don't use rails?

Tim

[polygonum]

I'd like to think that technology could make much of the trolley bus infrastructure considerably better and less problematic than earlier incarnations. For example, use supercapacitors, flywheels, fancy batteries, or something else to avoid the rats' nests across complex junctions and allow diversions for reasonable distances off-route. And automated mechanisms for raising and lowering the pickups.

[Nightjar]

A light rail system will typically be able to move about three times as many people per hour as a bus or trolley bus.

Colin Bignell

[Johny B Good]

I suppose the much lower energy cost per tonne kilometre you get using flanged wheels on solid steel track. Don't forget, modern control gear and motors allow for a more effective KERS.

Another factor is that you save on the weight of a large battery that would otherwise be needed in the absence of overhead trolley/tram wires.

One good plus point for electrically powered public transport is that it avoids high levels of local pollution in town centres and along the bus/tramway routes.

Admittedly this means a little extra pollution from the coal and gas fired power stations but since you're going to suffer the additional pollution anyway with ICE powered vehicles (in fact at an even higher level per horsepower delivered to the vehicle's driving wheels) you might as well route it more directly into the upper atmosphere than via the pavements of a busy city street.

In terms of energy efficiency and pollution factor, a 'Good Old Fashioned Tram' is at the top of the performance table followed by the trolley bus, followed by battery powered electric buses, followed by hybrid diesel electric.

Of all of those options, trams are the most mature of the technologies in public transport with well over a century of R&D worldwide to draw upon. I'd say a well designed tram system makes perfectly good financial and logistical sense today (in view of the problems of energy consumption and pollution issues, even more so).

[Tim+]

Funny how they all went out of business at a time when car ownership was much lower.

Well there you may have a point but I think it will be a long time before Edinburghers are convinced that their shiny new tram system was worth the hundreds of millions and all the disruption and loss of trade during construction.

Tim

[meow2222]

Some good points there. Certainly power station plus distribution plus electric motor is more energy efficient than a mobile diesel engine.

But Its a big pile of investment not required for buses. The absence of route flexibility is also a real downside.

NT

[Nightjar]

On 12/03/2014 00:28, [e-mail] wrote: ...

The sheer number of people you can move every hour is a big plus. The capacity of an Edinburgh tram is 332 people. The highest capacity double deck bus in regular service carries 95.

Colin Bignell

[MattyF]

This steam tram in Christchurch NZ has nine double-decker trailers. I estimate it will carry over 500 people, using one driver and one fireman, and maybe a conductor or two:

A trailer for a working steam tram is being built as we speak!

[Nightjar]

OOI did it operate with that many trailers, or was it simply a publicity photo, to demonstrate the superiority of steam over horse traction?

Colin Bignell