Pantograph vs. Trolley poles

[long island jack]

Ian, he also does switch stands

[298]

1 hour ago, Ian Blenk said:

Do you know a good source of trolley poles?

Cheers

Ian

 

I tend to use Bowser poles from Customtraxx. 

 

I believe the ones in the link are the same as the 4mm scale PC models etch that might be available over here, they are slightly different in design and use springs under compression.

[Derekl]

9 hours ago, BR60103 said:

Track point operation: I think most N.A. systems used the power on/coast method for streetcars.

 

The Johannesburg system (which was UK inspired and used similar equipment - the NA system is likely to be the same) used the power on/off to switch facing overhead points. The mechanics are reasonably straightforward - to travel straight, you coasted through with no power, but at limited speed (15 KPH, as I recall). To take the diversionary route you applied power on approach and passing through. The power drawn was shunted through an electromagnet which switched the frog.  There was an audible click as the frog switched, followed by a click as it released. You tended to drive with the sliding driver's door open, so that you could hear these clicks. Speed on diversionary route was also supposed to be maximum 15 kph - there was quite a high risk of dewirement if you exceeded that by any margin. The trick was to slow on approach, apply two notches of power on the power pedal and haul the handbrake on to control speed. As soon as you heard the second click you were okay and could proceed as appropriate.

If for any reason you applied brakes on passing through the frog, you could get the divergent route. The buses had regenerative braking which either used the resistors used to control traction current to take the brake load, but could also shunt it into the overhead if there was another bus in section under power to take the load. In that case, the power would shunt the electromagnet and switch the frog - embarrassing for the driver.

Because of the intricacies of undertaking these tasks wile negotiation a road corner, the junctions were usually some yard in advance, the wires running in parallel until the physical road junction.

I quite liked the trolley buses and enjoyed driving them and dealing successfully with these little challenges, but others found them somewhat terrifying!