What guage wire should I use to connect a train transformer to the O gauge lockons on the train track? thank, E.S

Hello, Don -

I hope I am correct you are asking about a Lionel ZW transformer for electric model trains.

I am personally not familiar with the transformer. However, I have found some information on the internet which may prove informative to you.

See:
https://dfarq.homeip.net/all-about-the-lionel-zw/

Plus, I found 3 PDF documents which are a series about repairing Lionel ZW transformers:
http://www.agtta.com/Tech-Tips/Tech-tip-ZW-repairs1.pdf
http://www.agtta.com/Tech-Tips/Tech-tip-ZW-repairs2.pdf
http://www.agtta.com/Tech-Tips/Tech-tip-ZW-repairs3.pdf

For the 3 PDF documents you will need Adobe Reader software (free) to open, download, save to your Documents folder, and print.

Assuming I am correct that you mean a Lionel ZW transformer, you may find more (and better) information on a forum for model train enthusiasts. This is a link to one such forum:
http://www.modeltrainforum.com/
If you are not familiar with that forum, you will need to first register to post on it. Registration is free.

Best wishes.

On a postwar LIONEL ZW TRANSFORMER, Yes the red light will come on if a short is present with the throttle on. As soon as the throttle lever is in the off position the red light will go off. Shortly followed by the automatic circuit breaker clicking, as it cools and resets. The short on the track may still be present but with the lever in the off position the red light will stay off. There are several variations of the ZW 275 Watt transformer, early and late "type R" models. Both work the same but are wired slightly different the early ZW uses two 6 volt bulbs and the "Type R" uses two 18 volt bulbs. Internally if there is a resister connected to the base of the red light it will use the 6 volt bulbs.

See illustration on page 9 of attached Manual.
http://www.lionel.com/media/servicedocuments/6420737921250ZWLManual.pdf

IfIam correct, the basic Polar Express came with just a whistle. There is an optional coal tender that has a better sound system in it...Whistle bell and steam sound also try reversing the power wires at the transformer or track

see attached pdf:
http://www.lionel.com/media/servicedocuments/71-4198-251.pdf

Have you cleaned your wheels & roller pickups?

There are 5 terminals on the bridge number them from outside to inside 1,2,3,4,5
Terminal 1 gets connected to the outside rails on a V,Z,VW,orZW transformer terminal U. The control button a #96 push button gets connected between terminals 2 and 3. Terminal 3 also gets a wire from A or B on a V or Z or Bor C on a VW/ZW. Terminal 4 gets connected to the transformer terminal D. Terminal 5 gets a wire to the lockon on the black bridge frame. The bridge needs 3 sections of track on each end seperated from the rest of the track as a stopping section remove the center rail pin on this section, This forms the stopping sections at each end of the bridge.

This does not appear to be a problem with the ZW. The XFMR does not know anything about train location on the track. It appears to be a track connection problem on the center or outside tracks or both. One way to identify a bad connection is to take a parallel wire from the common and hot terminal of the ZW and connect directly to the area of track where the train stops and slows down. If this cures the problem then I recommend checking the tightness of the three track connections. For both FasTrack and Tubular, crimp slightly the pin receiving holes in the end of the track.

Note: For both tubular and Fasrtrack it is recommended that common track power for any one section be input to the track at more than one point. In this way one bad outter or center conductor won't cause the train to slow up or stop.

If FasTrack, you can solder directly to the tabs on the track underside for a permanent connection.

The lockon is for tubular O or O-27 track. Slide the large part of the clip over the bottom flange of one outer rail....straight track works best and snap the cmaller clip onto the center rail. the two small terminals are your wire connections.

Answer a number of questions:
Is the tranformer power adequate for the train and is it a working tranformer?
Will the train run by connecting the wires directly to the two points of the train (wheels and center rail connector)?
Are the tracks new?
Is the lockon new?