Trolley Buses - any enthusiast?

[Jeff Layman]

Petrol-engined buses in London were heated - at least they were downstairs - and they also had open platforms at the back.

Upstairs all the heat from those bloody cigarettes no doubt kept that floor warm! :-)

Are you sure about that? I thought it remained a few inches above the roof, but below the wires. Most certainly, when manually lowered they had to be pulled down to clip into place on top of the bus. If it went up when it came lose, it could have hit the wire support damaging that or the pole itself.

Yep, kept in a long tube under the trolleybus.

[Chris J Dixon]

Think about it. The contact shoe which follows the wire is grooved, but only maintains pressure due to the spring forcing it upwards. Yes, dewirement can have consequences.

With modern railway pantographs, there are similar issues, but the controls are a little more sophisticated, and if it reaches the up-stop, it is automatically retracted. If it is wrapped round the catenary at this point, there is a lot of work to do.

Chris

[Jeff Layman]

I thought I remembered the conductor pushing the pole onto the wire to make contact - the connector at the end of the pole being shaped like /_\ if you see what I mean. Also, if the pole was spring-loaded, why not just replace it in position by means of a cord or rope attached to the end of the pole? Why the need for a stiff bamboo pole? When held down on top of the bus when parked or awaiting recovery, it could simply be pulled down to clip on to the roof of the bus (see my previous post), and the rope held on the back of the bus by a cleat.

The spring force needed at the roof end of a 4 m pole to keep the other end in contact if it didn't clip would have to be very high. But perhaps you are right - there are some Wikipedia articles such as

and which suggest the connector was a "loose fit". Unfortunately I couldn't find a close-up photo of a contactor used on trolleybuses of the era we are talking about.

Yes, but pantographs are directly below the wire and can exert a lot of force fairly easily as that force is applied straight up rather than at a pretty acute angle, and there are no side forces involved as there are with trolley poles.

[Paul]

Could be for heat in winter.

Paul

[AnthonyL]

There used to be a tight turning circle at a nearby terminus but not many drivers could get the angles right to do it without the trolley booms (not pantographs) coming off.

[AnthonyL]

And when running to catch one just as it's setting off. Many a flask in the satchel broken by landing flat on my back.

[AnthonyL]

I'm doubting it but the few things had heating in the '50's. They were a luxury add-on or a d-i-y accessory for cars.

[bert]

Mass use of driverless cars are some way off unless we are prepared to accept a few fatalities, just as we do with current vehicles.

[Tricky Dicky]

I do not think pantographs exert much pressure on the conductor. On the Manchester Metrolink which is based on a number of existing heavy rail routes the trams have to go under bridges not designed to accommodate overhead wires the conductors do slope down from normal height to pass under these bridges and it is quite noticeable how much movement there is in the pantographs To negotiate these bridges.

Richard

[bert]

Yes there was enough reach on the poles to move out and overtake another vehicle. I remember trolleys in Newcastle upon Tyne in the 60s.

[The Natural Philosopher]

I would say that it is closer than you think.

[The Natural Philosopher]

But they don't negotiate those sections at 125mph do they?

[bert]

Most level crossing are on ECML. HS2 adds capacity to WCML.

[bert]

Very expensive on flat land.

[bert]

So that's one. I am sure Network rail could find one on ECML that could be replaced by a bridge. Now what about the rest?

[bert]

Not that many level crossings on WCML

[Max Demian]

They'll just ban pedestrians and cyclists from the roads, and border them with perspex screens with sliding doors at intervals.

[Max Demian]

I'm pretty sure they were telescopic, so as to enable the bus to pass an inconsiderately parked vehicle.

(I have a vague memory that the driving test notes included a section on "changing lanes without de-wiring" and "steering a tracked vehicle with its tracks"; originally a driving licence allowed you to drive

*anything* on the road.)

[The Natural Philosopher]

No it isnt. Heck you can even build ramps out of steel.

Or you can tunnel under. Or dig a pond nearby and use the material for ramps

Lets say you need two 3 meter high ramp - at 1 in 10 slope that's 30 meters by 3 meters by about 10 meters wide

1800 cu m*. About 6000 tonnes at 30 tonnes a lorry load that is only 200 loads. Dunno what it would cost but Id guess abut £10 tonne max. £60,000.

Trivial.

*if the sides were sheer it would be half that but the sides wont be so I've overestimated

[The Natural Philosopher]

The classic one is the A10 at Foxton. Farmland all around. Could easily build a bridge alongside existing road and then divert the A10 onto it.

Or tunnel under the road.