Adding whistle control to an old, non-whistle transformer

[StevenGT]

Background: I'm trying to revive a decades-old layout, on an extreme budget and using a combination of my own childhood stuff (over 60 years old, Marx brand) and even older legacy stuff purchased several decades ago (mostly Lionel). My current dilemma/project is how to add whistle control for the whistle located in the tender that came with the older legacy smoker engine I recently purchased to expand my rolling stock, for a loop powered by a small, pre-whistle control Lionel transformer. After discovering the whistle in the tender and doing a bit of research, I was able to separately activate the whistle tender by putting it on an isolated section of track powered by an old DC HO transformer.

My question is whether I can add the DC-offset voltage to the AC power circuit for the engine, using a small legacy, AC-only, transformer (currently powering the loop) and the DC produced by the old HO transformer.

I'm reasonably sure that adding the second transformer in series (i.e., connecting the wire from the first track connector to one AC terminal, the second AC terminal to the first DC terminal, and the second DC terminal to the second track connector) would screw up the DC transformer and/or limit the AC amperage, but my question is whether I can just connect the transformers in parallel (both transformers connected to the same lockon). In theory, this should produce the DC offset needed to activate the whistle while allowing full AC motive power, but I'm concerned that this might not work, or worse, fry one (or both) the transformers. Yes, yes, I know the most elegant solution would be to just buy a(nother) transformer with whistle control, but 1) will my simplistic parallel-wiring solution work without damage, or 2) is there a simple (and preferably cheap!) way to isolate the transformers from each other and allow them to work together?

Sorry for the long-winded windup, but I hope my situation and concerns are clear. Thanks for any and all advice, in advance!

[lionelsoni]

No.

Lionel has made several devices over the years to add whistle control to simple transformers.  They all suffer from the lack of the extra 5-volt secondary winding in a whistle-capable transformer's built-in controller that keeps the track voltage approximately constant when the whistle is blown.  Instead they drop the voltage somewhat so that they can boost it when you blow the whistle.  So, unless your transformer has some voltage headroom at the speeds and loads that you run, these things may not be satisfactory.

It's not hard to make your own one of these and circuits have been posted many times on the forum.  Are you interested in help with that?

[sir james I]

If you can find one a Lionel 6-5906 whistle controller works well with all electronic whistle/bell boards, as mentioned above a little sluggish with the old whistles but usually work. Avoid the early controller that has a red box.(different number)

[lionelsoni]

Here's an old thread on the topic:  cs.trains.com/ctt/f/95/t/182590.aspx

[ADCX Rob]

StevenGT

..question is whether I can just connect the transformers in parallel (both transformers connected to the same lockon)...

No, can't do that... that will do the most damage.

StevenGT

...I'm reasonably sure that adding the second transformer in series (i.e., connecting the wire from the first track connector to one AC terminal, the second AC terminal to the first DC terminal, and the second DC terminal to the second track connector) would screw up the DC transformer and/or limit the AC amperage...

This is right on, for the most part - the series scheme will work, but with the limitations you have outlined. AND, you need to have a way to switch the DC supply in to(and out of) the circuit  - like a DPDT snap action switch that works fast enough to switch into the circuit w/o tripping the reverse unit."

The original K-Line 952 whistle controller worked in precisely this fashion, using a wall-wart type DC power supply and a fast-acting switch. It was not meant to be activated for long durations, and was triggering steam whistles in DC can-motored engines, which draw quite a bit less current than postwar Lionels.

 

[ericl007]

Well I'm sure this in unorthodox but here is what I did. I say a youtube video where someone attached a 9 volt battery to the tender, so I figured why not. So while the train was running with enough juice to activate the whistle I flashed the 9 volt to the tracks - the whistle blew fine. ext then i found an old 9 volt dc small plug in transformer added a standard button switch and that works fine.

[StevenGT]

lionelsoni

Here's an old thread on the topic:  cs.trains.com/ctt/f/95/t/182590.aspx

 

Thanks, Bob. I had actually seen that thread before I posted, but it seemed to apply only to adding bell control to a transformer that already had a built-in whistle controller. I'm hoping to cobble something together using some combination of small, vintage Lionel AC transformer(s) and a relatively modern (20-30 years old) DC transformer, and perhaps a handful of other components.

[StevenGT]

Any practical experience with just intermittently throwing the DC voltage across the AC driving the engine (i.e., both in parallel)? I suppose I could safely 'blow the whistle' by briefly applying the DC voltage *before* applying the AC voltage (sounding the whistle before starting), but I'd like to be able to briefly sound it while running, hopefully without blowing one or both transformers.

Your series idea is good, though I think it would work with just a quick-throw SPDT switch, by wiring one AC terminal directly to the track as usual, the other to the center "throw" part of the switch, and wiring one of the DC terminals to one of the other switch terminals and the other DC terminal to the remaining track connection, along with a wire to the other switch connector. Thus, in one position, the AC voltage would go directly from the AC transformer to the track, with the DC voltage isolated, and in the other, the AC voltage would be serially connected thrugh the DC transformer hopefully sounding the whistle while maintaining the engine's power. Make sense?

Again, I'm looking for any practical, real-world advice in solving the problem without destroying the equipment (my only reason for postponing the real-world test). Thanks to all who've replied already -- sorry for the delay in responding to the replies, but I'm apparently being moderated, and it was quite a few days before my original post appeared (apparently without notice to me), and I just got back to the forum today. In any event, thanks again to all!

[StevenGT]

sir james I

If you can find one a Lionel 6-5906 whistle controller works well with all electronic whistle/bell boards, as mentioned above a little sluggish with the old whistles but usually work. Avoid the early controller that has a red box.(different number)

 

So, if I get one of those units and wire it in series with my old, small, AC-only Lionel transformer, it would sound the tender whistle? How does it generate the DC offset voltage others have mentioned (and I have experimentally confirmed by placing the tender on track connected to a variable DC voltage)? Another post mentioned a wall wart powering another type of control unit, but I don't see how this control unit would do it.

[StevenGT]

After thinking through all (and responding to most) of the replies, it occured to me that I might be overthinking this a bit. Instead of risking relatively costly vintage transformers, I think I'll just dig out a low-voltage (5-9 volt) surplus DC wall wart and experiment. I doubt the DC voltage would (or could) damage the simple and primitive Lionel transformer (AFAICS an iron core step-down transformer and rheostat, no modern electronic components at all), especially if only intermittently applied. If the AC fries the wall wart, it's no great loss (one less widget to store in my basement electronics graveyard!). I'll post the result when/if I get around to trying it . . .

[StevenGT]

Mmm, well, my "don't overthink it" grand experiment was a near complete bust. Lower voltage wall warts (9 VDC or less) didn't seem to throw enough juice to activate the whistle (barely spun the motor when connected across the track terminals), and a 12 VDC wart not only spun the whistle motor (and I confirmed the polarization needed) but to my surprise also moved the engine, which I had assumed was AC only (at least, that is what I'd always been driving it with). When I briefly activated both the AC transformer *and* the 12 VDC wall wart in parallel, the train slowed, the lighted lockon dimmed and the whistle failed to activate. *sigh* Back to the drawing board . . .

[StevenGT]

Quick update: having failed to come up with a cheap DIY solution, I broke down and bought a couple of used Lionel whistle/bell control units (a relative bargain - I got both for $5 at a local hobby shop), wired one up and . . . nada. Tried both of the units, and switched around the wires, tried running the engine with the tender, and the tender alone, and no combination resulted in a peep out of the whistle tender. I seem to be out of options -- any suggestions? Oh, and is there any way to get off moderation on this forum? It's certainly not conducive to a free conversation to have to wait a week or so to have your submitted posts appear, and in my decades of on-line postings I've never been moderated, other than briefly at most.