Functioning catenary?

[tverskaya]

Already many, many years I've been wondering about this, but have never dared to ask, but just to show my ignorance: Is is possible to have two trains moving independently on the same track if one is fed through the track and one gets it's juice through a catenary? And this, of course, without getting into fancy digital systems. With my very basic knowledge of wiring, I could think of both a reason why it would and a reason why it wouldn't work.

So what's the deal? Is this the easy (apart from modeling the catenary) solution for running more than one train on the same bit of track or not?

 

[interurban]

Hi tverskaya,

Yes it is possible, and I have done it on my last L/O which is no more.

The trick is to have the wheels on your overhead pickup insulated on the rail compatible with your 2 rail pickup Does that make sense to you?


You will have to change one wheel set so all one side is insulated the other side will have front and back wheel picking up power from the same rail, the over head supplies the power to the other side of the motor


The two rail unit should work as normal.

So from the controller one wire to one rail the other wire to the other rail AND the pole.
You have to know which way to put your traction unit on the rail.

 

[60103]

About 30 years ago streetcar modellers had what was called the "Detroit" method of control. It only worked for cars that only went forward, but it gave independant control of 4 cars on one track.
Basic: 2 cars pick up from the right hand rail. There is a rectifier (diode) wired into the circuit, but in opposite directions. The AC power supply has a pair of oppositely aimed rectifiers, each teamed with a variable resistor, so that one resistor controls the one car and the other, the other.
The process is repeated for the other rail.
There may be a bit of wiring fiddle to get the cars running forward.

The normal catenary system is similar to the old Trix Twin system, where Trix used the center rail as common and the outer rails as independant returns. They also had a catenary version, I think, but the limit was 3 trains independant.

 

[tverskaya]

Chris' solution looks like the simpler one from the description. But that seems to imply only one controller, so the two trains would run synchronously. But something I had in mind would be the following:

Controller one, connected to catenary and rail 1.
Controller two, connected to rail 2 and rail 1.

I would just imagine a big mess connecting the two controller's cirquits in such a way (obviously the correct direction/polarity would already limit some of the operation), but in essence, this is identical to that Trix system then?