What’s the best postwar Lionel transformer? Arguably there might be two contenders. But the Lionel KW and ZW definitely stand above the rest. Here are their advantages and disadvantages.
Arguably the best Lionel postwar transformer is the one you have. But if you’re looking for an upgrade, there are two worth considering above all the others: the Lionel KW and ZW.
Is it safe to use a postwar transformer?
There’s a lot of FUD floating around about postwar transformers. I know where the idea came from, and don’t want to dignify it by elaborating much. They had a point, that modern transformers are rated on how much power they output, while vintage transformers were rated on how much they consume. So a modern transformer gives you about 30% more power than a vintage transformer with the same rating. But they went on to imply they are unsafe, without backing it up.
It’s not really even a matter of efficiency. A modern transformer outputs more power, but it also consumes more power. It’s just a difference in how they’re measured. Modern transformers are measured more honestly. But that has nothing to do with safety or reliability. If a transformer passes these checks, it’s safe to use.
If you’re still worried about safety or reliability, consider this: Virtually every home in the United States had a doorbell installed when it was built. That doorbell runs on 10-24 volts, a similar range to what a Lionel transformer uses. When was the last time you heard of one of those causing a problem or failing?
The Buick: Lionel’s KW
If you’re going to run more than one train, you can pair up two smaller transformers, or you can look at the two-handled transformers.
The 190-watt Lionel KW was the second biggest and second best transformer of the postwar era. If your layout is bigger than 4×8, you may actually find trains run a bit better with a KW than with a smaller transformer.
The KW used to be really expensive, but since Lionel started making big transformers again, you can get a KW for what a 1033 used to cost, which makes it a very nice bargain today on a rugged and powerful transformer with an impressive presence. I’ve talked more about the KW here.
The major downside to a KW is the design of the two throttles. You turn the A and B throttles in opposite directions to speed up or slow down the train. Turning the A throttle down speeds that train up, but turning the B throttle down slows that train down. You get used to it if it’s your only transformer, but if not, keep an easy hand on the KW throttle until you remember when up is up or when it’s down.
The other downside to a KW is the lack of a 14 volt power output. You just get 6, 18, and 20 volts. Accessories will run at 18 volts, but if they have 14 volt bulbs in them, the bulbs burn out quickly.
The KW is the second best Lionel postwar transformer, but I notice a bigger dropoff from the KW to the smaller models than I do from the ZW to the KW. In this case, calling it second best isn’t an insult.
The Cadillac: Lionel’s ZW
Z is #26 in the alphabet but ZW is #1 in Lionel postwar transformers.
The iconic and legendary 270-watt Lionel ZW was the biggest and best transformer Lionel made in the postwar era. It’s expensive, but the same factors that drove KW prices down are also driving ZW prices down. Just not quite as much.
I can remember a time when a Lionel ZW would set you back $275. Today, with some luck, you can get one for closer to $100. It’s a bargain at that price.
The ZW doesn’t have confusing controls. The only downside is the lack of fixed-voltage outputs. Most people use the dial controls to power accessories, and just dial in the voltage they want.
I’ve written more about the Lionel ZW here.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.
The one caveat to using a post war transformer with modern electronic controlled equipment is that a simple derailment could cause a spike in the circuit that could fry the electrical circuit board in the equipment. This is a very expensive risk that can easily and inexpensively be avoided. Just add some TVS Diodes: https://www.ebay.com/itm/Lionel-ZW-Transformer-Circuit-Protection-8-1-5KE36CA-TVS-Diodes-30-8V-1500W-/202448427429
The original Lionel ZW transformer was built to last almost forever and is highly serviceable. If you add TVS diodes to the outputs and fuse the track power leads these work great. Internally they rely on a simple reliable design (think Variac) and won’t fail like the more modern transformers which rely on IC chips, and transistors made of “unobtainium”.