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Sorry to ask such a basic question.  If I run DC power from my transformer to 027 tracks, will AC engines run on it OK?  Forward, reverse, whistle tender etc?  Would I need to have a 125 watt or greater transformer to run two engines?

Thanks for all experiences and advice.  All is welcome.



Original Post

Postwar engines will run on DC, as the motors are of the ''universal'' AC/DC type.

Whistle tenders cannot run on a DC powered layout, as a DC voltage from the transformer whistle control is used to activate the tender relay to blow the whistle - hence the whistle (or diesel horn) would blow constantly.

The KW transformer rated at 190 watts input power was designed to run 2 trains separately.



Last edited by TrainLarry


Thanks very much for this information.  Throughout my entire life, I have always suggested "McGiver remedies" that upset traditionalists. 

As I understand it, the problem with running an AC powered locomotive with a whistle tender on a DC track is that the DC current would make the whistle blow non-stop.  So, why couldn't I just disable the whistle inside the AC tender (or  buy one without a working whistle), then buy a junky AC tender with a working whistle, mount it underneath the layout board, or inside a small building, and run a separate DC wire to it with a push button switch in the circuit.  When I want a train whistle to blow, I just press down on the button switch on my control panel, and the AC tender whistle goes off. 

Wouldn't this work?    

I don't think, for a very basic layout, that anyone is really going to know whether the whistle being blown is from the tender car in tow on the track, or in the center of the layout from a fixed position.

Thanks for all replies and critiques.






Manny, like Larry said, most will run, but it's good to ask questions first. Like some of the more recent pre-LionChief engines with DC motors that have TrainSounds, the DC current will damage the sound boards.

Also a note on steamers. Again, what Larry said is true about postwar steam engine tenders. But I have a bunch of the modern era 4-4-2 starter set steam engines with DC can motors and whistle. I have not pulled the engine circuit boards from these, so they run F-N-R on either AC or DC. Using DC current with the tenders that came with these engines, the whistle will only blow when you change the direction button, which activates the relay in those tenders. Changing the direction button will not affect the direction of the locomotive so long as it has the reverse circuit board in it.

Yes, you need a big enough DC power source with enough amperage in it. Or there's another way: Lionel at one time made a conversion box so you could use the large postwar Lionel transformers with the DC only G gauge trains.

This is what I use with my Lionel 1033. I have two separate wiring circuits to the train track, with a shut off switch. One for direct AC to the track (with a shutoff bypass on the conversion box) and another thru the conversion box putting rectified DC current to the track.

If you were to buy a specific DC power pack, you'd probably want one intended for G gauge trains, as the typical HO/N scale ones would lack the amperage to run most 3-rail trains.

Years ago I did an experiment using a small HO power pack. It would run a dual motored K-Line S-2 engine, but any added lighted cars would trip the power pack. It would run a Lionel 4-4-2 steamer, but only with the smoke unit turned off and no lighted cars. So the small HO power packs won't do much for our larger power hungry trains.

Last edited by brianel_k-lineguy

I'm all for "McGiver" type creativity, especially when there's no other viable solution out there, but here - to disable one tender; buy another or make a dummy; mount one tender under the layout, wire it up to a switch and a separate DC power source and try and make believe the whistle is coming from the train instead of underneath the layout, seems more like creating a complicated solution when no real problem exists.

Since you want/need the extra power to run two trains, why not just invest in the KW transformer that will give you more than enough power and two separate handles and has AC power to boot to let you keep and run your AC powered engine and whistle tender w/o having to cannibalize anything ?


I have two Lionel whistles from tenders mounted in a building with open windows on both of my layouts train boards and I have push button switches for both whistles at my control panels by each of three the Lionel LW transformers.  The whistles are powered by one my two 12vac 30 to 40 watt transformers used mostly for building lights. These whistles do NOT have a relay an are connected directly to a 12vac transformer.The whistles blow every time not like a whistle tender that uses a dc relay to trigger the whistle.  These relays depend on the tender pickups being clean and working and the relay contacts and pulling in to work making them iffy many times.  This saves me lots of money too as I do not have to buy whistle coal tenders for my steam locomotives which number some 40 or so.  I normally do not buy coal tenders and but make them from shells bought cheaply and make bases from steel building siding or roofing scraps and add trucks from train shows.  I have made two Vanderbilt coal tenders recently from scratch using mailing tubes and junked coal tender shells.  You can see them on my train layout post link I gave you before. 

I have two Bachmann diesel horns that come in an oil or diesel storage tank also powered by 12 vac lighting transformer so I do not have to worry about buying working diesel horns in locos either.  They have push button switches at all three LW' too.

The Lionel LW transformer is the most powerful single train transformer Lionel made.  The LW will run two trains at a time and does so often on my layout that has two loops wired with relays to allow two train operation without one over taking the other.  My  three LW's only run trains.  Lighting has its own transformers and the 31 Marx 1590 switches and uncoupling tracks have their own 14 vac transformer.


Last edited by Choo Choo Charlie

Dc fed to an ac board really shouldn't do anything bad unless it was an awful design. Every ac cycle has a + and - wave; dc is either a + or - wave (a wall of water until turned off if you will; from a battery, or pulsed + or -, not true dc.)

Now some logic circuits are known to use ac , split the dc+ and dc- and use them for separate system sections. (Walthers O SD-¿??) So something might not work right on dc, but it should live.

Run ac to a dc only motor or unrectified board and you cook it. (most can motors & magnets for the field vs coil field)

The only exception I can envision might be setting it into a write mode or dump by accident.

Most trains will need the volume off or older, whistle motor switch added.

Smoke unit elements will perform differently, but again, the smoke unitsboard wont care either.

A diode is a one way gate. A bridge rectifier is a package of four diode aimed to form a 4 door corral. Ac goes in, dc pulses come out. One of the arrangements is often found on our boards, but there are some exceptions.

Learn to find them and use diodes and BRs. They are very reliable solid state items, not complicated logic like command can have.

A capacitor ,similar to a battery, vs filter/disc type, can smooth pulses to smooth and quiet things if you want.  Fry something? Try fuses   For the price of a handful of diodes, br, led and resitor variety packs... oh well.  (not that hard)

Ac is wild horses and given access to two corral doors so they can come and go as needed , 60 crossings per second, 30 each (+/-) direction.

In the corral one remaining gate keeps entry going head first only, inline into a high wall stall (dc+) and loops around and dumps at the remaining one way gate letting them back into the corral where they will choose the easiest path to follow at that second.

"The 4 diodes" can be tapped off in other ways too.  My point is more about what to look for before you test ac on a board or motor. Motor fields & board rectification.

98.8 of ac items dont care much about dc.  Id mind the motor and goodies for heat, but otherwise pretty fearlessly.

Some folk hated the buzzing some eunits have, and clacking E-units. The intro of sounds and command both made its function more important than nostalgia. The buzz is at 60hz Tape or a frame tweak can shut one up sometimes,lol



@Mannyrock posted:
So, why couldn't I just disable the whistle inside the AC tender (or  buy one without a working whistle), then buy a junky AC tender with a working whistle, mount it underneath the layout board, or inside a small building, and run a separate DC wire to it with a push button switch in the circuit.  When I want a train whistle to blow, I just press down on the button switch on my control panel, and the AC tender whistle goes off.  Wouldn't this work?

Whistling Billboard !

@Mannyrock posted:

When did Lionel start putting circuit boards in their engines and tenders?   I will only be using 1970s stock and earlier. Nothing modern.  All old school.



Manny, I don't recall the exact year, but it was sometime in the late 1980's.

We read here lots of threads about failed circuit boards, but outside of my own error, I have not have one of these basic (and primitive by today's electronic features) reverse unit circuit boards fail on me. They're not as complex, so there's not as much to go wrong. Just food for thought.

Everything you're hearing here in answer to your questions might sound complicated at first. For me, it was just an on-going process of change.

I was running my layout normally on AC at first. Then one day, while working on an Industrial Switcher, I accidentally shorted and ruined the reverse circuit board. It was my fault. But then I got to thinking, "well why couldn't I run the layout on DC also, so then I could add some weight to these small engines."

And because I have a bunch of small sized MPC era steam engines, I also have a stationary whistle only I took the internal whistle box assembly from a tender and mounted inside the shell of a Lionel SP caboose on the layout, which I use as a yard office. On a small layout, the whistle sound coming from a stationary billboard, or some kind of building is not all that noticeable.

For me, and other guys like Choo Choo Charlie, part of the fun is the creativity of doing things yourself. Not to mention, it does help to make the hobby more affordable. 

You'll drool over something new eventually. It doesn't mean you have to dive in, but it's hard not give a head nod at some of the new eventually.  I'm PostWar oriented and still run conventional power. I only have a few modernn era items (80s-today). But I do try not lock myself into decisions based on the age of the tech I might choose to do a job, I want to consider many paths before I decide. 

There isn't anything magical about boards. They do the same basic jobs they did 75 years ago only without moving parts or the size. E.g. a transistor is just a tiny, silent, relay and they make a stupidly HUGE variety of specs to choose from too.

What's cheap, easy, or there on hand often wins over the best of plans though 😁

I run two old Radio Shack units, 4a&4.5a constant 12vdc, a 60s Allstate automotive 8a battery charger with a nicely working self reset internal breaker, a coin op/video game's universal dc supply (+12,-12,9, +5,-5 &+3v) and BR rectified dc off an American Flyer ac unit. If my power goes out there are two car batteries to run off of. 😜   Ive ran off a 4a dc power supply for an electric food cooler and via automotive DC to AC converters. (I have 9 layouts, most micros under 36"sq.).... and off a 24vac 4a hippie neon(?) lamp driver


Where I need throttle; one or two diodes eat .75-1.5v or they are bypassed by one on/off spst toggle. There are rows of these toggles along side a chain of diodes (or diode chain circle, tab to tab on a 11pos rotory sw. if you don't have 40+ toggles kicking around like I did..and only 1 rotory) It works better than you might imagine. Any switch up is a boost, any down it slows, throwing 4or 5 with a palmed hand, no problem. How long is your hand? (plus each end has a 3pos toggle and off ability. So three ways to kill power fast 


125w. It might handle two small-med locos and a few small/light weight cars. 

If you mean the LW, that only has one throttle. Two LW would be great.

I think the SW or TW is two throttle. That case style tends to not follow lionels normal tap outlines. I had one or both as a kid and wasn't too impressed.

KW or VW 180w are better. (VW price tends to be higher because it is a ZW twin, but deals are common too because it is odd and lower power than ZWs)

These can deliver more than the 180w half of 90w to track #A

 If track B is only wanting 50w, track A has 130w to use or visa versa. Nice.

Two 1033s 90w is decent too, (gotta phase two, not hard. I did it with gramps by phone a few times when very young. Not hard to find how, here, Lionel via Youtube, etc,)   

A prewar transformer? A different look but still great stuff


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