LW Transformer - Help Desperately Needed

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LW Transformer - Help Desperately Needed

  • I'm turning to the this forum community for help.  I purchased a reconditioned LW Transformer from an Ebay seller who will remain nameless, but whose reputation is outstanding.  When it arrived, I hooked it up the exact same way as my TW Transformer:  I put the A wire on the A post and ran it through the left eyelet of the lockon and put the U wire on the U post and ran it through the right eyelet of the lockon.  I then placed/snapped the lockon from the middle rail of the three rail track to the rail track closest to me.  The trains ran strong, but I could not get sound on my Lionel Tender or on my K line by Lionel NH Alco. 

     I sent the transformer back to the seller indicating that it didn't sound and he tested it on a variety of engines/tenders:  postwar 1950 or so tender and a 1992 alco and all was well.  I'm a person of my word so I'm keeping the purchase because obvioulsy I must be a dummy when it comes to using this thing.

     Can someone help me (understanding that I am not an expert on wiring, layouts, etc) explain what to do once the LW is sent back to me?  Bonus points for anyone that will share some digital photos of the wires running from a LW to the track with the lockon attached so I can figure this thing out. 

     Thanks in advance for any help.  This is driving me nuts.

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  • Modern whistles are polarity sensitive, so you probably had the polarity incorrect for the engines you're running.

    On most larger Lionel transformers, you connect the U post to the outer rail. The LW is opposite of this-you need to connect the A post to the outer rail and the U post to the center rail.

    This should get your whistles working correctly.

    Ben TCA 09-63474
  • Thank you for the response.  Now I need you to help me further.  You're talking about polarity and such but I'm not knowledgeable about this type of terminology.  Should I just reverse the way that I snap the lockon on the track so the "tab" is on the rail closest to me rather than the middle rail?  I really need "LW Instructions for Dummies."
  • Leave the lockon snapped onto the track the same way.

    You just need to connect "U" to clip 1 on the lockon(the left hand clip) and "A" to clip 2(the right hand clip).

    This should make the whistle work correctly. 

    Ben TCA 09-63474
  • I am puzzled that the TW worked, wired that way.  It may have been rebuilt with the rectifier reversed from the original design.  That would have been the result if the rebuilder followed the Lionel schematic.

    2343, a transformer normally puts out AC, which has no polarity associated with it and can be connected to the track either way.  But when you try to blow the whistle, a rectifier inside the transformer case makes some DC voltage that is added to the AC.  This does have a polarity that depends on how you hook it up to the track.  However, the postwar locomotives didn't care about that and worked with either connection--all their whistles cared about was whether there was any DC at all, of either polarity.  The modern locomotives do care and take one polarity to mean "whistle" and the other to mean "bell" (if any).  The whistle polarity has the center rail positive and the outside rails negative.

    For some perverse reason, all the schematic diagrams for Lionel postwar transformers show the rectifier polarity backwards from the way they were actually built.

    Bob Nelson

  • 2343 if you don't have this you may want to print these out:

  • Thanks.  Based on the schematic and since I don't have the LW back yet, there seems to be two A posts.  Does it matter which one I use with the U post to provide power to the track and for sounding the whistle/horn?
  • No.  They're connected together right inside the case.

    Bob Nelson

  • I learned the hard way. It a lot easier and more satisfying, at least to me, to operate with a modern transformer like a lionel CW-80.

    I bought two LW's and though both do a fine job powering my trains. Getting the whistle to blow on modern equipment using the built in lw button circuit can prove to be a time consuming headache.

    You can get a new cw on ebay, pick a reputable seller, for 35- 45 dollars. You might want to try that. I'm going to keep one lw for sentimental reasons and may eventually successfully wire up internally a new diode correctly.  I'd just get a cw-80. 


  • I think that the voltage is significantly less with a cw80 than a LW?

  • The LW is rated at 125w and the CW-80 at 80w.  I know the LW puts out 0-20v through the A-U posts, the CW-80 I think is 0-18v.  Now the 2v difference isn't going to be much in terms of opperating, but the CW-80 will trip faster than the LW if a short occurs (derailment) and it has buttons for the Whistle and Horn (which the LW does not).

    I use my CW-80 when I want to power modern equipment on a small layout, and the LW to power Postwar equipment.
  • 2343,

    "Postwar" transformers such as the type LW were rated on their rated input (in watts) rather than their output.  Modern "transformers, such as the CW80 are rated on their output wattage. Often it is more useful to compare "current" rather than "power." The LW was rated at 5.5 to 6; whereas the CW80 "runs into a wall" at 5 amps.

    That is not the total story by any means. The output voltages many vary some what, and the shape of the output waves of alternating current vary also, with the CW80 putting out a "cropped" wave rather than a pure sine wave. Therefore they are a bit difficult to compare on paper.

    The CW slowly ramps up power when the "direction" button is pressed to change from neutral to forward (or reverse); but when pressed while in forward (or reverse) (to go to neutral," the power is cut immediately. The throttle lever on the CW reacts immediately to raise or reduce the power; but inertia and momementum conspire to make this less obvious than one might think. In other words, the behavior of the train won't necessarily react immediately. You can check this by putting a single illuminated caboose on the track and watching how the brightness of its lamp changes as you manipulate the various controls. In some cases the action of the lamp, which produces a much lower load than a train, will be instantaneous; in others it will "ramp." (I am indebted to ADCX Rob for clarifying this for me.)

    There are literally reams of material availble. At the "Library" at Olsen's Toy Trains, look under "Transformers"  [generic] and "Transformers, LW." Be advised that there are errors in both the Olsen's online material and in the Owner's Manual for the CW80. One can also search the archives of the various forums. There are errors there also. It can be quite confusing, unfortunately.


    *For what it's worth, I, too, generally run trains with modern electronics on modern transformers; and trains with postwar whistles and horns with postwar transformers.

  •  lionelsoni wrote:

    For some perverse reason, all the schematic diagrams for Lionel postwar transformers show the rectifier polarity backwards from the way they were actually built.

    I had no idea this was the case! Explains some head scratching I was doing about a year ago! Thanks for that info.



    "Of course I crash them! Why else would a grown man play with Trains!".. Gomez Addams
  •  The March 2007 issue of Classic Toy Trains contained a short article on the failure of Lionel to be consistent with their transformer markings.

    The same issue of the "variable" output versus the "neutral" return posts affect the 1033, 1044, the TW, RW as well as the LW.

    On a single loop of track, there should be no noticeable difference in operation of postwar equipment.  The major problem would come if one tried to tie all the "neutral" legs of several transformers together.  If you applied a vaiable output to a neutral leg, you could get a voltage mismatch that is potentially destructive.  Don't ask how I know this.

  • jaki30 wrote,

    "Don't ask how I know this." I am far too polite to ask that. (Was anyone injured?) Smile [:)]

    Excellent post. I hope your readers pay strict attention to the modifier/qualifiers, such as "postwar." They can make all the difference.

    There are really four issues here:'

    1. At some point, ages ago, Lionel decided to make the U post the neutral (return, common, black, or whatever one wants to call it) on transformers that were designed to power multiple loops of track where one could easily operate more than one train at a time. Among these was the postwar ZW. The U posts were generally supposed to be connected to the outside rail.

    However, on transformers that were intended to power only a single loop of of track and run only one train at a  time, such as the popular 1033, the U post was customarily connected to the center rail. The instructions gave the operator the option of selecting from several choices what post he wanted to connect to the outside rail. A chart of these combinations is available in the "Library" at the Olsen's Toy Train website under the generic heading   "Transformers." In some cases, the pages that list transformers by model number add a bit.

    2. For reasons that few can recall today, Lionel sometimes violated it's own rules and manufactured items that were quite puzzling -- in whole or in part. One example concerns the whistle rectifiers. It didn't matter much at the time, because neither the whistle nor the horn cared which wire was hooked to what. With the introduction of bells and other sound effects, how things were hooked-up suddenly made a whole lot of difference.

    3. In some instances Lionel mixed- or messed-up the instructions such that they failed to clarify the above.

    4. This is not ancient history: the early CW80's, which can still be found for sale "new in the box," suffer from all three of the the above problems. 

    Hope this puts a slightly different slant on the problem.