Live catenary

Original poster discussed this option and ruled it out as he wanted locos without O/H.

- Nigel

That brings back recollection of a fairly common method of wiring street cars and interurbans. The truck picking up the right rail is connected to the rear trolley hold-down hook, and that on the left rail to the front hook. The motor is connected to the two trolley poles. When both poles are down, the hooks complete a circuit and the car runs as a conventional 2-rail model. Put up either pole to live overhead wire and the car runs in that direction. This does require the two rails under wire to be connected together. Geezer

David Bromage skriver:

Extremely helpfull.

Have I claimed that ?

Have you seen "my" model railway - theres a lot of cantenary

It is not worth it.

Klaus

I've seen layouts with catenary in Z. I don't know if it was a live catenary, though.

If you do that, you need to put 25kV onto your overhead........But don't touch the wires when your trains are running..

Bevan

But the caternary does not pick up dirt from the wheels of trains, pick up is from the underside so does not pick up dust and there is more friction in the contact so tending to keep it clean. Of course if you haven't run it for while it will probably need cleaning. In the real world no special trains required to put cleaner on it as has to be done on the Southern third rail, well that's oil for de-icing.

Chris

Most UK locos only have a single pantograph.

Chris

Sounds like a great idea, except that last sentence confuses me. Wouldn't connecting them together cause a dead short?

To be honest I think it is rather helpful. It is one of those things that sounds like a good idea and makes a great intellectual challenge to work out how to do it, But in reality you can not see electricity flowing though the pantograph. No observer would know how a model is powered from just looking at it. Yes, you will know it is really working and probably feel proud of what you have achieved but ultimately it will be more work than the end result justifies. So just go with a cosmetic system and don't worry about it.

I'm describing a wiring scheme that let trolley modelers run on two rail layouts, or on other live overhead trolley layouts. Only the latter would have the running rails grounded together. And there would be no short - the wire is positive and the track is negative - just like Lionel's 3rd rail. Geezer

To be honest, it's not.

You can't see electricity flowing through the wheels either. If what you could and couldn't see mattered, nobody would have used that new fangled electricity in the first place when modellers already had clockwork and steam.

Cheers David

David Bromage skriver:

Yes it is.

If you want the loco to detect what rail (left or right) is used with the voltage an the catenary on a analog set you need to detect either a short circuit og on the voltage.

If you like to detect a short circuit (this short circuit is between the catenary and one of the rails, unless you want to drive it by 2 seperate transformers). This detection circuit needs a power supply - and can be done by mounting a battery inside the loco.

You can allso detect on the voltage, but if you like to run the setup with 2 different transformers for either catenary and "2-rail" it is impossible to do. If you only run on 1 transformer for alle it is not quite impossible, but again the "detection circuit" needs to be powered somehow.

To power the detection circuit (unless you want batteries) you need the pantographs to be the one og the supply lines and one of the tracks to be another. So you mount 2 resistors between the wheel pickups, the resistors should be big enough (ohms) to not load your trnsformer to mucht, but small enough to still be able to power your circuit. When the power for the circuit is done it needs to be rectified , stabellized and regulated to a low voltage. On this low voltage you hook up a uP that detects where the power is coming from and controls a "switch" that chooses which wheel pickup that sould power the motor.

Klaus

"Klaus D. Mikkelsen" skriver:

-cut-

David - any comments ?

Klaus

David Bromage skriver:

David...................

Klaus