ZW circuit breaker

Yes, Sensata/Airpax "instant-trip" magnetic circuit breakers are signifcantly faster than thermal breakers. Links to sources of Sensata/Airpax breakers here. Make sure the number after the first dash is a zero, which indicates "instant trip." The number after the second dash is the current rating and has an "A" after it. Examples: PP11-0-7.50A-OC-V (PP = push-pull) or PR11-0-8.00A-XX-V (PR = push to reset). If the current draw is approaching the rating of the circuit breaker, you will hear a buzzing sound. If the buzzing is constant, just go up a step or two in the current rating. In your case, I might recommend the 8A version.

@Steve H and others have written a lot about Sensata/Airpax breakers, including here and here and here.

Thank you very much.   I ordered the 8 amp per your recommendation.

@jps32016 posted:

Thank you very much.   I only operate one train at a time so protecting just the one throttle will do the trick?

Yes. Are you using the ZW for accessory power, too? If so, you should have an external circuit breaker for that, too.

If your accessories lack sophisticated electronics, you could get away with a thermal breaker, and unless you have a lot of incandescent lights, you could probably use one with a lower current rating than your track-power breaker. Or just get two Sensata/Airpax magnetic breakers, they're relatively inexpensive. Regardless of which type of breaker you use for your accessory power, you should have something other than what is in the ZW.

All the accessories, including switches and uncouplers, are old Lionel.  This is for my leftover tubular stuff home layout that is actually on my workshop floor.  Never had any problems with them but will consider your suggestions.  What would you recommend for that?  My earlier Gargraves/MTH DCS  layout (didn't have space for it anymore) I donated to a museum and run shows during the season (pix at strasburgmuseum.org).  It has circuit breakers/fuse, and capacitor discharge protection.  I did get a couple electronic reverse engines so figured best not to press my luck.  Thanks again for your help.

We use a 5 amp instant self re-setting breaker here at the shop.  Harry

@jps32016 posted:

All the accessories, including switches and uncouplers, are old Lionel.  This is for my leftover tubular stuff home layout that is actually on my workshop floor.  Never had any problems with them but will consider your suggestions.  What would you recommend for that?  My earlier Gargraves/MTH DCS  layout (didn't have space for it anymore) I donated to a museum and run shows during the season (pix at strasburgmuseum.org).  It has circuit breakers/fuse, and capacitor discharge protection.  I did get a couple electronic reverse engines so figured best not to press my luck.  Thanks again for your help.

I would recommend a Sensata/Airpax magnetic circuit breaker for your track and another for your accessory power. A problem with thermal breakers, as I understand it, is that if the current is just over the rating, they take a long time to trip—many seconds. Compared to the cost of locomotives, accessories, and a transformer, $32 for a pair of 5A or 8A or circuit breakers ($20 each for 7.5A) is not much. I like push-pull and push-to-reset of auto-resetting, because it gives you time to find and clear the fault. (The pull feature on a push-pull allows you to use it as another kill switch, which I like, too.)

All prior advice has been on target IMHO, but if most/all of your rolling stock is PW and/or electronics-free, you can get away with much less expensive ($5 or so each) thermal circuit breakers, which are adequate to prevent the thermal melt-downs from shorts that had previously plagued my PW ZW-powered layout (mostly Marx). If you *do* have electronics you must protect, the more expensive fast-acting breakers are the best bet, and FWIW I'd also add TVS diodes across each circuit to protect against transient voltage spikes, which can sometimes fry a vulnerable ICB as quick as a dead short on the track! Good luck!

@Steve Tyler posted:

All prior advice has been on target IMHO, but if most/all of your rolling stock is PW and/or electronics-free, you can get away with much less expensive ($5 or so each) thermal circuit breakers, which are adequate to prevent the thermal melt-downs from shorts that had previously plagued my PW ZW-powered layout (mostly Marx). If you *do* have electronics you must protect, the more expensive fast-acting breakers are the best bet, and FWIW I'd also add TVS diodes across each circuit to protect against transient voltage spikes, which can sometimes fry a vulnerable ICB as quick as a dead short on the track! Good luck!

The OP does have some RailSounds equipment and modern reverse boards. Good call on the TVS diode reminder.

@Matt_GNo27 posted:

Yes, Sensata/Airpax "instant-trip" magnetic circuit breakers are signifcantly faster than thermal breakers. Links to sources of Sensata/Airpax breakers here. Make sure the number after the first dash is a zero, which indicates "instant trip." The number after the second dash is the current rating and has an "A" after it. Examples: PP11-0-7.50A-OC-V (PP = push-pull) or PR11-0-8.00A-XX-V (PR = push to reset). If the current draw is approaching the rating of the circuit breaker, you will hear a buzzing sound. If the buzzing is constant, just go up a step or two in the current rating. In your case, I might recommend the 8A version.

@Steve H and others have written a lot about Sensata/Airpax breakers, including here and here and here.

Got the 8 amp.  Works great.  Thanks.  Had to service a bunch of mth motherboards that weren't protected like I thought.