Automatic switch-off of track section power on system power-off

[ITG]

Hi,

I have a lift-out bridge section over a doorway, and forgot (despite planning to do so - doh!) to wire it such a way that the track section either side of the lift-out section is ‘off’ when the removable section is not in place; obviously to prevent trains plummeting into the gap.

i could go back and redo, but it occurs to me to ask if there’s a cut-out device which I could place in line to the power feeds to the track sections either side of the bridge, which needed to be reset to ‘on’ if the overall DCC system had been switched off. Thus, I would need to switch on the DCC system, and then flick a switch to re-power the either-side sections. This reduces the likelihood of a plummet significantly. I think it would be easier to place such a device in the dropper wire than rewire the bridge.

Any ideas?

ian

[Oldddudders]

Quite easy, really. On either side of the gap, you establish a section that is not connected to the track-bus. The track-bus ends at the gap with two contacts. The insert has contacts either side to meet those, and as well as the rails on the section, these feed to other contacts which meet contacts from the isolated sections. Every time you put the bridge in place it completes the circuit. 

[Michael Hodgson]

A microswtich activated by bridge section in/out of place, perhaps via a relay, putting a dead short between the feed to the running rails, this activating the overload cut-out. Detect the locking bolts if you have them.

 

Or, more elegantly if your controller has an emergency stop facility, arrange for it to operate that.

[LNERGE]

As everything I run has asymmetric brake active I’ve put a control on the signals reading over the lift out section.  I’ve put in slightly larger plug couplers to the lift out section and put a simple loop that controls a relay and that relay is cut into the HR circuit. Plug couplers out means the relay is down. 

[WIMorrison]

I think you use iTrain? If not ignore this comment.

 

You create a switch on the flap which you connect to a 10k resistor (depending on feedback units in use) and then create an action within iTrain that looks for that feedack becoming active. When it becomes active you use iTrain to make the block (or blocks) unavailable and iTrain will stop any trains crossing the flap until you put it back down.

 

I have set up several people this way.

[RFS]

I just used a simple push-to-break switch under the flap. Originally, I had a Lenz LZV100 and that had a feature for this, whereby you could set up an emergency stop button by wiring it across the the E and M terminals. When I replaced the Lenz with a Z21, I simply wired the switch across the bus so now you get a short circuit that stops the whole layout. Crude but effective and cheap. The lowering of the flap breaks the connection and ends the short.

 

[Dominion]

I use PSX circuit breakers for different power districts on my layout. They can each be given an accessory address like a turn out and be turned on and off by sending an accessory command. They normally start up “on” but a simple CV change can make them start in the off position until their accessory address is used to send a 1 or normal command. I have my loco depot set up like that so that it starts up off, and a push button linked to a spare input on an NCE mini panel sends the address to power it up. 

I think the solutions in previous replies are simpler and also protect the gap if you remove the flap during a session and leave the power on.

However it would do what you asked in your opening post, if you treated the 2 tracks either side of the flap as a power district set to be off at power up. I would probably only do it that way if I happened to have those bits of electronics knocking around already. 

If you have any male and female plugs and sockets you could route power so that the track sections either side rely on plugs or sockets only present on the removable flap. That would be much cheaper than the electronics. It is the same conceptually as Olddudders solution but uses manual plugs instead of aligning contacts if that installation looks tricky. 

[ITG]

Thanks all for many potentially workable solutions.

 

13 hours ago, WIMorrison said:

I think you use iTrain? If not ignore this comment.

 

You create a switch on the flap which you connect to a 10k resistor (depending on feedback units in use) and then create an action within iTrain that looks for that feedack becoming active. When it becomes active you use iTrain to make the block (or blocks) unavailable and iTrain will stop any trains crossing the flap until you put it back down.

 

I have set up several people this way.

Thanks Iain. Yes, I am on the way to using iTrain. I’m using DIgikejis DR4088s and Yamorc YD6016 current sensors, so one of those two units will be relevant for what you suggest. Are either workable for this use? I assume this switch/resistor is simply linked to one feedback contact on the unit?

I haven’t graduated to using actions yet but will cross that bridge (no pun intended!) when I get there. No risk yet of trains plummeting as nothing is yet running, except on the iTrain screen. (Latest query awaits (probably your) attention on iTrain forum - LOL)

Ian

[ITG]

On 19/02/2024 at 18:47, WIMorrison said:

I think you use iTrain? If not ignore this comment.

 

You create a switch on the flap which you connect to a 10k resistor (depending on feedback units in use) and then create an action within iTrain that looks for that feedack becoming active. When it becomes active you use iTrain to make the block (or blocks) unavailable and iTrain will stop any trains crossing the flap until you put it back down.

 

I have set up several people this way.

@WIMorrison can I just check, never having ventured into the world of resistors before? Is this what I’d need?

https://uk.rs-online.com/web/p/through-hole-resistors/0131895?cm_mmc=UK-PLA-DS3A-_-google-_-CFS_UK_EN_TE_Whoop_PO4700202468-_-(GB:Whoop!)+Passive+Components-_-131895&matchtype=&pla-302166681338&gad_source=1&gclid=CjwKCAiAuNGuBhAkEiwAGId4am1NOFkI4cJsJpcQj-oNTRFK5iyvX5VUh5kxo7tR2peTKRP5lWIgOxoC3QsQAvD_BwE&gclsrc=aw.ds

 

with a push-to-break switch ( so when bridge is in place, there is no circuit)? And how is the wiring done? Power via cable from current sensing unit to one side of switch, cable from other side of switch to resistor, and then where? Back to current sensing unit?

Help much appreciated.

Ian