Verdict on the Lionel Fastrack Uncoupler Push Button?

John, it's really a gamble.  Some of the factory controllers are fine other's aren't.  I still use them, but first I take them apart and tweak the mechanisms.  I also solder the riveted electrical connections.  Which ever kind of button you use, the uncouplers are susceptible to melting the roadbed (and possibly the coil wire itself) if left energized too long, which is why I now install a PTC in-line with the electromagnet.  I recommend the Bourns MF-R050.  These PTCs are cheap insurance against melt-downs, regardless of the cause.

Great idea about the PTC Steve.  How are you "tweaking" the push buttons, stretching the long return spring?

John

Tweaking: I haven't done anything to the springs.  It's a matter of careful examination and minor adjustments.

Just the contacts.  I make sure they're aligned laterally and also that the overlap is sufficient not to cause binding between the contact ends.

OK Steve.  Easy enough.  I have no idea where "Dave" came from.  Senior moment

Thanks,

John

I can verify the plastic button on the controller can stick with the result you mentioned.  Melted plastic and ruined device.

I can’t believe this. I installed two of these when I built my layout in December, 2011, and have never had any problems with them. 🤔

@Yellowstone Special posted:

I can’t believe this. I installed two of these when I built my layout in December, 2011, and have never had any problems with them. 🤔

It may or may not happen.  Here's one that did on an operating track using the factory activation button that stuck:

If yours haven't stuck in over 10 years, the buttons are probably fine.  Not all of them are.

It comes down to a choice of between taking a ~ $40 gamble using the unmodified factory button or buying insurance (PTC resettable fuse) for less than a dollar a piece.

BTW, the PTC can be installed pretty much anywhere in series with the power or control circuit for the coil.  It doesn't require pulling out the uncoupler track to retrofit.

Steve,

What made you pick that particular PTC?  Trip current 1A

John

Amazing! Thanks for the tip, Steve. 👍

I wonder if some of these are sticking and melting because they are being operated at command voltages from the track.

I don't use mine alot, but wired them on auxillary/ accessory power per the owners manual set at 10v and haven't had a problem

The sticking on mine was strictly mechanical. The button would physically bind, and not return to off. It had nothing to do with voltage.

I've never experienced a problem with the buttons in my somewhat limited experience with them.  My 'operating section' track had a problem where a jumper wire melted, but I think that was due to something else.

Last week I bought these small surface mount project boxes that can easily be used for layout buttons and switches.  7 for $12.  They are thin enough to cut openings with an Xacto knife or utility knife and easily spray painted.  They would be perfect for an on layout DIY pushbutton.

John

@Craftech posted:

Steve,

What made you pick that particular PTC?  Trip current 1A

John

Tried and true, recommended/endorsed in numerous discussions here on the OGR forum by knowledgeable members.  Here are a few:

https://ogrforum.com/...4#154589723624465404

https://ogrforum.com/...39#74354735445230739

https://ogrforum.com/...5#158111058609425145

@stan2004 posted:

I don't have/use the FasTrack uncoupler, but per the OGR community info in the Electrical Reference section, the FasTrack coil draws about 1.8 Amps.

From the datasheet for the MF-R050, the nominal "trip" time at 1.8 Amps is about 5 seconds.

To be clear, there is what amounts to "wear and tear" on these resettable devices.  I suppose one can look at it philosophically as a tradeoff to get multi-use or resettable performance vs. one-and-done of a traditional fuse.  So to your point about "risk," I don't think you will see any meaningful change/degradation in uncoupling  action.  I'd think there would be real comfort value to confirming it "works" and you installed it correctly.  In my opinion of course!

So, for example, if you hold down the button for 20 seconds and nothing happens (other than the coil getting hotter and hotter) then I'd terminate the experiment and double-check your wiring and such.

Ok.  I'm sold

Thanks,

John

@RickO posted:

I wonder if some of these are sticking and melting because they are being operated at command voltages from the track.

I don't use mine alot, but wired them on auxillary/ accessory power per the owners manual set at 10v and haven't had a problem

Good point Rick.  Use of a higher voltage than 10-12 volts AC increases heating in the coil for a given ON time.  18V DC (Lion Chief wall wart) is even worse for overheating these coils than comparable AC voltage.

I'm in the process of installing a few Fastrack uncoupling sections on my layout and I'm replacing the stock buttons based on the stories I've read here on the forum. I purchased these momentary SPST switches form Amazon and 3D printed a panel to mount them in. Here's the 3D printed part with one of the switches in place

Not related to uncoupling sections, but I did something similar when I added the 24" Atlas TT to my layout. The first are SPST toggles for whisker tracks & sidings and the other is a momentary DPDT rocker for the turntable itself.