Older Lionel transformers with newer Lionel locomotives (Chief, Plus, and Plus 2.0)

Some say no problem, others say don’t run new trains with the old transformers.   Personally, I would not run new trains with older transformers.    Replacing boards in engines is not worth taking the chance.

Bottom line as a best practice, everything, especially things with sensitive electronics, should be protected with strategic external breakers and TVS diodes regardless of power source/transformer. It is absolute hogwash that classic transformers cannot be used with modern trains or that modern transformers don't need additional protections.

Ditch any LionChief DC WalWart supplies for track power. There is over a century of tradition with AC on the 3 rails and just about anything ever made will operate on AC. The same is not true of DC - it can actually be destructive to products. As for the KW, 1033, or any transformer of  any era, use of strategic TVS diodes and external breakers is a must. You can build a bank of small transformers linked together in a common ground wiring scheme for multiple throttles and dedicated accessory buss sources.

Why do we need these extra breakers and TVS diodes? Well, typical operation of our trains cause voltage spikes caused by collapsing electromagnetic fields generated by items on the layout (relays, solenoids, motors, derailments etc).

A short video about those transient voltage spikes (educational and more extreme than we would see on our layouts):

1.5KE36CA is more appropriate for classic transformers that have a voltage boost for the whistle/horn function which can approach 25VAC.

1.5KE33CA is more appropriate for modern power supplies capped at a nominal 18VAC.

These are available from online electronics suppliers of all sorts such as DigiKey and Mouser.

For external breakers, there are many thoughts and beliefs and turf wars. However, even if your power source has protections, it is much easier to identify issues and provide tuned protection when the "mains" is distributed through child circuits. Commercially, the PCX-AC breakers are well regarded - a bit pricey to some, but less than a repair/replacement of burned up components. However, note that they may not be ideal for conventional operations as they loose their effectiveness at lower voltages. AirPax breakers are also a favorite and can work on a wider voltage range. There is always the good old classic prewar Lionel #91 that also works well for some. Of course, there will be those who don't use a full gamut of protection with out problems, but why take the risk?

@Engineer RJP posted:

circuit breakers that may not be fast enough to keep your electronics in the new locomotives from frying out.

There are no circuit breakers that are fast enough to keep your electronics in the new locomotives from frying out.  You are describing a current protection solution, when in actuality you need a voltage protection solution in the form of transient voltage suppression.

I run 6 ZW's on my layout with no problems.  Old/new doesn't matter, just install a inline fast blow fuse and your good to go.

Have run like this for over ten years with no issues.  I run TMCC, Legacy and DCS as well as conventional.

@NYC 428 posted:

... just install a inline fast blow fuse and your good to go.

That will protect from over-current. What are you doing about voltage spikes?  The damage from transients is ongoing/continuous even in the absence of short circuits, and is cumulative.

There is no reason why you can't use an old transformer with modern equipment. The older transformers will work perfectly fine in conventional operation they way they always have, and they will work fine as a power source for a lionchief engine of any kind. In some ways older transformers can be better, they put out pure sine wave, which works well with almost any engine, the chopped sine wave they use on some modern transformers can have problems with some engines.

There are two downsides to older transformers:

1) Make sure they have been maintained,that the cord is in good shape and that the internal components, the rollers that actually make contact, the rectifier the while uses, all are in good shape. Some people take a transformer out of mothballs that is like 60 years old and use it and that isn't safe.

2)On older transformers the circuit breaker was designed to protect the transformer, and it is really slow. Postwar equipment didn't care, but newer stuff is sensitive.  So as others have written you would need a quick blow circuit breaker or fuse (some people use auto fuses, which are cheap and easy to get).  Basically any power output from the transformer should have such protection.

The other critical thing as others have mentioned is a tvs diode across the power output (between hot and ground) on the transformer. This prevents a transient voltage spike, basically a voltage surge, to get to engines on the track, spikes like that are deadly to modern electronic circuits. They are cheap and easy to get, do a search on the forum and you will find a lot of threads about them, what to use and how to get them. They are ridiculously easy, they go between the U (common) and the variable track votage terminal.

The advantage of modern transformers is they are built with modern engines in mind, so have fast blow breakers and tvs included (though I have heard debates about that). Given the size of your layout and your needs, you likely could use an older transformer or transformers just fine.

One thing you might want to think of, when running engines conventionally, you could get a powermaster and a command base (either legacy or cab1/tmcc) , that allows you to control conventional engine speed remotely, the powermaser varies the voltage to the track, and they work fine with an older transformer, too.

@bigkid posted:

they [TVS Diodes] go between the U (common) and the variable track votage terminal.

U is not always the Common terminal. There are many ways to utilize many of the classic transformers:

@bigkid posted:

The advantage of modern transformers is they are built with modern engines in mind, so have fast blow breakers and tvs included (though I have heard debates about that).

In any transformer, the circuit breaker is sized for the transformer, not the load - hence the need for strategic external breakers regardless. As for TVS being incorporated, some power delivery components like a TIU do have them, but never assume, and still supplement. You can read all over the forum discussing the internal surface mount TVS diodes fail shorting out TIU channels. It could be argued that strategic use of external TVS diodes would reduce the failure rate of the internal TVS diodes which are not as easily replaced as external ones.

Keep it simple. I have been using Z-1000 bricks for years with DCS,Legacy and conventional engines. The first sign of trouble like a derailment they trip fast and kill the power. I haven’t fried anything yet.  

@NYC 428 posted:

I run 6 ZW's on my layout with no problems.  Old/new doesn't matter, just install a inline fast blow fuse and your good to go.

Have run like this for over ten years with no issues.

@Chris Lonero posted:

Keep it simple. I have been using Z-1000 bricks for years with DCS,Legacy and conventional engines. The first sign of trouble like a derailment they trip fast and kill the power. I haven’t fried anything yet.  

Can you get buy without external breakers and TVS diodes - some claim to, but why take the risk? It is extremely cost effective insurance to utilize proper power distribution practices and realize that no transformer or power supply can have optimal power protection for every conceivable distribution setup. Then, consider the manufacturers spotty availability on some of the replacement circuit boards for products! It becomes maddening when you see fellow hobbyist cut corners or tune out because it is "all electro-babble nonsense". Reminiscent of those who rejected seat belt use because they haven't needed them before...

@bmoran4 posted:

Bottom line as a best practice, everything, especially things with sensitive electronics, should be protected with strategic external breakers and TVS diodes regardless of power source/transformer. It is absolute hogwash that classic transformers cannot be used with modern trains or that modern transformers don't need additional protections.

...

1.5KE36CA is more appropriate for classic transformers that have a voltage boost for the whistle/horn function which can approach 25VAC.

1.5KE33CA is more appropriate for modern poser supplies capped at a nominal 18VAC.

These are available from online electronics suppliers of all sorts such as DigiKey and Mouser.

...

I just checked Mouser for the 1.5KE36CA and 1.5KE33CA.  Both are well below $1 each (plus shipping, of course), and the inline breakers are just a few bucks each.  At that price, why wouldn't anyone add the protection?

Would a TVS Diode provide the necessary protection simply connected across the 1 and 2 contacts on a separate Lockon?

@Johnsgg1, a TVS diode across terminals 1 & 2 of a CTC or LTC Lockon is one effective way I've seen them deployed.

Yes, if you are using lockons then you could put the TVS across the lockon tabs, you would need to do that for any of the track power lockons .

With modern transformers, you prob don't need an external breaker, the internal breakers likely are fast trip as well, but as others have said putting an external breaker on can't hurt (and you have the option of putting a lower value one if you feel the transformer one is too high). TVS are cheap enough that even if something has TVS built into it, kind of makes sense to use them anyhow IMO.  You can use an old transformer and never have problems unprotected, for my Christmas around the tree layout I had modern equipment with boards in it, and didn't have any problems, running my old KW, but why risk it for something cheap like fast blow breakers or fuses and TVS?

@Vinny26 posted:

Some say no problem, others say don’t run new trains with the old transformers.   Personally, I would not run new trains with older transformers.    Replacing boards in engines is not worth taking the chance.

Thanks!  I am thinking that I may just run some modern stuff on the outside rail with a new transformer, and just keep all the old stuff together.  I am just getting back into O gauge after many decades doing N and HO (I find the stuff too small for my aging eyes!).

@bmoran4 posted:

@Johnsgg1, a TVS diode across terminals 1 & 2 of a CTC or LTC Lockon is one effective way I've seen them deployed.

Thanks, that makes sense.

@bigkid posted:

With modern transformers, you prob don't need an external breaker, the internal breakers likely are fast trip as well, but as others have said putting an external breaker on can't hurt (and you have the option of putting a lower value one if you feel the transformer one is too high). TVS are cheap enough that even if something has TVS built into it, kind of makes sense to use them anyhow IMO.  You can use an old transformer and never have problems unprotected, for my Christmas around the tree layout I had modern equipment with boards in it, and didn't have any problems, running my old KW, but why risk it for something cheap like fast blow breakers or fuses and TVS?

Yeah, I like the idea of a little money spent now to save you a problem with expensive locomotives if you fry out the circuit boards and have to get them repaired as well as you have not prevented the problem going forward.

@bigkid posted:

Yes, if you are using lockons then you could put the TVS across the lockon tabs, you would need to do that for any of the track power lockons .

Thanks - I see how that would work.

@Chris Lonero posted:

Keep it simple. I have been using Z-1000 bricks for years with DCS,Legacy and conventional engines. The first sign of trouble like a derailment they trip fast and kill the power. I haven’t fried anything yet.  

Ahhhh . . .  I have access to one of them from a friend who doesn't need it and I could get it cheap.

@bigkid posted:

There is no reason why you can't use an old transformer with modern equipment. The older transformers will work perfectly fine in conventional operation they way they always have, and they will work fine as a power source for a lionchief engine of any kind. In some ways older transformers can be better, they put out pure sine wave, which works well with almost any engine, the chopped sine wave they use on some modern transformers can have problems with some engines.

There are two downsides to older transformers:

1) Make sure they have been maintained,that the cord is in good shape and that the internal components, the rollers that actually make contact, the rectifier the while uses, all are in good shape. Some people take a transformer out of mothballs that is like 60 years old and use it and that isn't safe.

2)On older transformers the circuit breaker was designed to protect the transformer, and it is really slow. Postwar equipment didn't care, but newer stuff is sensitive.  So as others have written you would need a quick blow circuit breaker or fuse (some people use auto fuses, which are cheap and easy to get).  Basically any power output from the transformer should have such protection.

The other critical thing as others have mentioned is a tvs diode across the power output (between hot and ground) on the transformer. This prevents a transient voltage spike, basically a voltage surge, to get to engines on the track, spikes like that are deadly to modern electronic circuits. They are cheap and easy to get, do a search on the forum and you will find a lot of threads about them, what to use and how to get them. They are ridiculously easy, they go between the U (common) and the variable track votage terminal.

The advantage of modern transformers is they are built with modern engines in mind, so have fast blow breakers and tvs included (though I have heard debates about that). Given the size of your layout and your needs, you likely could use an older transformer or transformers just fine.

One thing you might want to think of, when running engines conventionally, you could get a powermaster and a command base (either legacy or cab1/tmcc) , that allows you to control conventional engine speed remotely, the powermaser varies the voltage to the track, and they work fine with an older transformer, too.

Thanks!  Yes the KW has been maintained, got this from my LHS where they do repairs of locomotives and transformers (have done this for years, have some good dudes who work with this stuff) - I know that it was looked at on the inside and a new power cord was added.

Regardless of what you choose, the addition of some type of external protection (TVS, fast blow fuse) is always a good idea.

@NYC 428 posted:

...the addition of some type of external protection (TVS, fast blow fuse) is always a good idea.

TVS mandatory, external fuse(bad idea)/breaker(good idea) optional.