Problem with Fx Brick's P40 Switch Track

[coreyg]

I just got finished replacing the tie bars for my P40 Switch Track from Fx Bricks.  It gave me an opportunity of looking pretty closely at the switch itself and I started wondering how it turned off power on the inactive pathway.  I just didn't see a way.  At first I thought the Switch Rail's connection may somehow depend on if it's switched or not, but it was backwards from that.  So, tonight I powered the track up and switched back and forth.  And, at all times, both the diverging route and the straight route were powered. (Yes, if I pulled the jumper, there was no power on the diverging route at all times regardless of how the switch was positioned which is not a solution.)

So, how would you have a siding for a train if it's always powered regardless of how the switch is positioned?  The only possible way I can think of is this switch requires DCC so the train itself knows when it can go or not.

I really hope I have something wrong because if I don't, then the P40 Switch Track is not compatible with 9v trains.  Yes, it can deliver power, but it can't shut it off if the path is not active.

Think of a yard ladder.  Every lane would be powered at all times.  There's no stopping trains then.  All of the trains would be moving.

Please let me know I'm missing something because if I'm not I spent a lot of money for nothing that I can use and I'm stuck with Lego's switches for a long time to come. (Yes, I'm stuck on 9v and happy with it, but trying to improve it.)

------ Later addition -----

Ok, I just reread the FAQ that's included in the product guide:

>Does changing the switch route also switch the electrical power to the route?

>No.  The P40 switch does not switch the electrical power between the straight and diverging routes.  Both routes are "live" and their corresponding rails are connected together.

Then how would you have a siding to park a train?  Or a yard ladder with multiple trains parked?  All of the track would be powered at all times.

Are they assuming DCC for everything?

-Corey

Edited March 12 by coreyg
combined the 2 messages together (sort of)

[zephyr1934]

This sounds like a question first to be directed to FxBricks customer support. I do not have any of their switches yet, but I had expressed concern over the fact that the original prototype powered both tracks all the time. Shortly before release of these switches, I believe Michael Gail had said that no, in the production switches there is a jumper on the underside. If you remove the jumper it will function like a normal lego 9v switch (but with better curvature). Now like the Lego 9v switches, the outside rail is always powered since it is a continuous strip of metal, it is only the inside rail that will lose continuity without the jumper.

[Narissis]

Finally a post appeared that made me stop lurking and actually sign up to answer, haha.

So, yes, with FX Track switches, all routes are electrically live at all times. This, according to Michael's own writings, is "for our own good," though I personally feel there should be an option to make them work like LEGO 9V switches.

That being said, the intent isn't that you use third-party DCC, but rather that the switches be used as part of the larger FX Track ecosystem which will, eventually, include motors that are designed to be more easily compatible with the PFx Brick, or in the case of the 'smart' motors, will have that functionality integrated. The problem, of course, is that presently there is no way to feed power from  the rails through a PFx Brick to a PF or PU motor with off-the-shelf parts. I think this is probably one reason why Michael is prioritizing the power pickup axle over the FX Bricks motors in his product roadmap - to enable the use of a PFx Brick with FX Track and a train motor as early as possible.

In the meantime, with only 'dumb' 9V motors available and the switches not cutting power from diverging routes, we'll have to make do. For my part, I will probably just lift the motor bogie to the side a bit on any train I have parked. Not ideal, but it'll hold me over until the smart FX Bricks motors arrive. Another option would be to insert one length of plastic track near the front of each siding and nudge the motor onto and off of that. Either way, it does mean employing the 'hand of God' but I've observed at many model railroad shows that this is not exactly verboten since all kinds of model railways occasionally need a little persuasion. :P

In the future, there may also be FX Track isolators available, which would provide a means for turning off those diverging routes. But I have yet to hear firm plans from Michael on those, so I wouldn't expect them anytime soon.

For my part, my plan is to upgrade to the smart motors when they're available, which should be sooner than whenever we get isolators.

One other thing: the jumper isolation, as zephyr pointed out, only works for one rail - that's because it's designed for crossovers, in which case when you remove the jumper from each of the two connected switches, then each one isolates one of the two rails from the connected loop so the ultimate effect is isolating both loops from one another. They're not meant to be used for any feature contained within a single loop; you would still get a circuit conflict if you built a return curve, for instance, even with the jumper removed. In cases like that you would need to insert some other kind of isolation, like including a single piece of S1.6 plastic rail, or taping the contact surface between two rails. In the case of a return loop, this would of course mean the polarity would reverse across that gap so a standard 9V motor would get stuck, but a motor controlled by a PFx Brick or some other kind of controller that doesn't care about polarity would be able to handle it just fine.

[coreyg]

Thanks for the info.  It makes these switches useless to me for sidings or yard ladders but for crossovers, they'll work nice and with closer main lines, so that'll be nice to have.

I'm very disappointed that the switches don't work for sidings or yard ladders with existing motors.  All of those pictures of yard ladders using the P40 switch and no way of currently using them.

Some day, I may go to DCC and then it won't matter.

Thanks,

Corey

[Narissis]

I think the manual workarounds make it not completely a dealbreaker, however it does mean having to have all parts of the yard within arm's reach, which can be a problem on big layouts.

Hopefully the smart motors arrive within the year so we can have an in-system control solution!

[Andy Glascott]

I’m not familiar enough with the components to name them accurately but it’s easy enough to make a switch that will isolate a section of track for you in a siding.

First, place a piece of tape between two sections of track where they connect, just on one side of the track, then repeat this further down, say 2 track sections or 32 studs, again on the same side of the track. This creates a section without power.

Second, connect one end of a wire to the track on one side of one of the pieces of tape, for arguments sake, about 12 inches/30 cm long and connect the other end of it to the track on the other side of the tape. This bypasses the tape and provides power to the “dead” section. Now fit a simple on/off switch in the middle of the length of wire. When it is on, power reaches the dead section of track, when it is off, it doesn’t. Use a longer length of wire to have the switch closer to your control panel. The old 12v track system uses exactly this set up.

If you use this in a ladder situation you only need one piece of tape as there is no power reaching the track from the end of the siding. 

Edited March 12 by Andy Glascott
Typo

[Duq]

I wouldn't say useless... I was also hoping that without the jumper they would work like the old 9V switches. What this means is you need a connector to each track in the yard ladder. I also means Fx should hurry up with their connectors because the old ones are going for stupid money on BL and the rubber wires are crumbling...

[coreyg]

I think the easiest way for a single siding to work with the P40 Switch is to use the connector that the jumper is attached to on the inner divergent track.  If that's a short, there's power, if it's an open, that rail is dead.  You could very easily attach a 2 conductor wire to that and bring it out for a switch (or in my case, I'd attach it to a relay that is controlled by the same power I use to control the motor that will flip the switch).  So, for a single siding, it's pretty easy and for me, self contained with no extra changes outside the switch.

However, for a yard ladder to work, it also needs to deactivate one of the rails on the straight route or it'll give power to both tracks and if there's a train parked there, both trains will have power.  Deactivating the other line in addition to powering the divergent rail starts getting a lot more complicated.  I personally am out on that complexity especially if you start thinking about a yard ladder of 3 or 4 tracks/lines.

A side note:  I've completely given up on the Lego track connectors after I found I lost 1 full volt between my controller and the track with a mid-sized train.  Some of the voltage was that connector but most of it was from the 2x2 plate connectors that Lego uses, so I've switched to soldering onto the side of the track and using better connectors to the wire. Michael Gale in one of his interviews mentioned some type of design issue with Lego's 2x2 plate connector and they fixed whatever that issue that was, so maybe their connectors will be better.

Thanks for the feedback.  I would not have thought of the single siding solution without Andy's comments.

-Corey