Heavy Duty power supply

The KW is certainly a robust transformer, and pretty cheap as well.  I'd have a circuit breaker in series as the internal "breaker" really only protects the transformer.  For a basically unattended display like this, I'd want a circuit breaker that requires manual reset, you don't want it continually trying to apply voltage if there's a short or derailment.

If running modern trains add a TVS also . described here

http://www.jcstudiosinc.com/BlogShowThread?id=486&categoryId=

Dale H

The Lionel KW is certainly one of the well regarded transformers of the post war era.  They are readily available and prices seem to have come down in recent years.  It is worth considering why KWs and other post war transformers are not as hotly sought after as they were through the 1990s.

John and Dale have both mentioned considerations that come with the use of a post war transformer for modern trains.  If you use one it is prudent to add extra protection for the trains with modern breakers and/or transient voltage suppressors.

I think it is also worth considering the type of duty you are asking a 50 or 60 year old transformer to perform.  Do you really want to rely on such an old electrical device 42 hours a week?

KWs are relatively inexpensive now due in part to the fact that we have had several modern alternatives for over a decade now.  Today the Z-4000 is the benchmark large transformer and the Z-1000 sets the standard for train set transformers.  They come out of the box with modern circuit protection and a UL listing.

If you knew a young couple who was getting married would you consider giving them a 60 year old toaster as a wedding gift?  Why use a 60 year old electrical appliance for a high duty cycle application in a children's museum?

If you are running modern trains and have a modern power supply you will have some good options to add play value for the kids.  You could stick with conventional control but give access to a bell and whistle button.  Command equipped locomotives could be operated in conventional mode on the museum layout but be preset with sound settings limited to appropriate levels for the environment.

If you make the jump to command more options open up.  One area super market has a display layout that operates periodically according to a set command control program.  And the Edmonds Historical Museum has the Pacific Fast Mail display layout and now operates Proto 3 locomotives on it with the DCS remote commander.  The sound makes that a big hit with kids of all ages. 

The TVS dale mentions is good as well, I put them into each locomotive when I open them up for other service as well. 

I personally would have no problem running the display on a KW or other PW transformer, as long as you provide the circuit protection downstream from the transformer.  There is very little to go wrong with a KW in continuous use, that's one of the reasons they're still running a ton of layouts after 60 years!.  I'd like a Z-4000, but I can have a bunch of KW's for the same money.  You do sacrifice the bell feature that you get with a modern transformer, which is something to consider.

Guys, Thanks for the comments.  Z4000's are beyond our budget but I am thinking of the discontinued MRC AH 501 which are 135 watts.  We would get 4.  The alternative is three KWs with fast circuit breakers.  I believe the Carnegie Museum uses KWs with no problem.  I found this handy panel which would meet our needs.

http://scottsodds-n-ends.com/circuit_breakers.htm

We are avoiding command control for reliability reasons at this point. The target audience is young kids in the 3 to 8 year range.

We have built benchwork, and put down the roadbed and track and assembled a number of buildings.  We will resume in late October.

The thing about KW's is there is virtually nothing to go wrong, and they're bulletproof.  Any of the modern electronic transformers are more prone to failure, no matter how robust they claim they are.  If you use the variable voltage a lot, the rollers will have to be replaced at some point.

I am building a rather large layout 1400 sq feet. To power the trains at York I purchased 2, Kws and 2, ZWs. The ZWs cost $135 each and the Kws $45 each. I replaced the power cord on one of them that was bad. As long as they are in good condition I have no hesitation about using them. As long as you add the breaker to protect the smaller layout wiring they are safe IMO.  The breaker in the transformer will protect it if working properly. If you are not familiar with fixing these types of things, have a competent person do it. Regardless of transformer used I would add the TVS if running anything modern. I also found that pure sine wave transformers (all the old ones) cause less problems with electronic compatibility.

The Z 4000 and Lionel modern ZW are good IMO but very expensive as far as dollars per watt.

As far as old electronics I have a collection of juke boxes and pinball machines all 60 years old or more and once reconditioned work as well as anything modern. 

I however would not leave any such electronic device old or new completely unattended. There is actually a warning about this in the Z4000 manual. Make sure someone checks periodically.

If you see my blog I have some push button circuits there made from modular timers..

Dale H