What's your opinion? Transformer big enough?

[Banks]

In the question and answer section of the last issue a reader asked about his starter set train slowing on an large oval. It seemed as if he was only supplying power at one point.
He was told he needed a bigger transformer. I don't under stand. If a train set transformer runs a train OK on a small oval it will do just fine on a large oval with some additional feeders.
I'm afraid this fellow will buy a larger transformer and with only one feeder will have the same problem.

What's your opinion?

[lionelsoni]

You're right.  I have complained about CTT on this point; but they just don't make the distinction between power and voltage.  I think some of this superstition comes from the fact that some of the higher-powered transformers, like the Z and ZW, just happen to be higher-voltage ones too, compared to the 1033, for example.  So someone whose trains are slowing down due to undervoltage takes the advice to get more power, incidentally gets more voltage too, and thinks that his (mis)understanding of the problem is confirmed.

[Ole Timer]

 Yep .... more than likely it may even be track connections on the larger layout at different points also .... and new hobbyists don't realize if they pile on cars and more accessories using power the weight and current draw will slow them down also . Too many variables to blame just one thing on . That's why I won't make any calls on those topics ... I'd have to be there in person to check their system out .  

[Laurastom]

As said there are many variables and many points of power loss in the system. Transformer voltage and rated power output are the first two. Our challenge is to get this to the train with minimal loss. The first loss point is the resistance of the wire connecting the transformer to the track terminal ( I am an AF operator, I think it is called a lockon in Lionel land.) For AF layouts 18 ga. is fine, for Lionel if you have a 2 motor engine, 4 lighted passenger cars etc. I would use 14 or 16ga.wire. The next point of loss is the connection between the track terminal and the track. I will come back to this. Next is the resistance through the rail, for original Gilbert AF this is very low. Next is the resistance at the track pin joints, again this can be quite large. Finally there is the resistance between the rail and the pickup, keep it clean to minimize this, but it is of course independent of the size of the layout. In Flyerland we are limited to where we can place track terminals so that we do not defeat the selective power routing feature of the Gilbert turnouts through back feeding. This is not an issue with Lionel.

I found an electrically conductive grease called OX-Gard made by GB Electrical of Milwaukee. I have been using it for the last 8 years. I buy it at OSH. Since most of the resistance is at the joints and connections applying a very small amount of this on each track pin and on the track terminal connectors when assembling the layout will eliminate all the power loss issues until one gets into larger layouts.I have a 6x12 holiday layout that I operate with just two track terminals, one on each loop. It has 12 original Gilbert turnouts for sidings, passing tracks and loop interconnections. I once left it up for 4 years and it ran as well then as when first assembled. To run the trains I use the MRC Dual Power O27 with the wired remotes plus a Legacy controller to operate the new S Gauge Big Boy. All run great with no slowing anywhere on the layout. When using the Legacy I set the voltage at the transformer output to about 14 volts so I do not burn out all the original AF bulbs. I hope this helps.

Tom

[Bob.M]

Laurastom

As said there are many variables and many points of power loss in the system. Transformer voltage and rated power output are the first two.

 

It is not always the voltage that causes trains to slow down. My new K-Line K2780 Interurbans slow to a crawl on curve tracks, and especially on esses. They then go excessively fast at the furthest distance from the transformer, on a long straight track. The slowdown happens for all the trains, but it is more noticeable for these.

[Laurastom]

 Right, that sure sounds like a mechanical cause, not electrical. All one can do is make sure the wheel sets of all the equipment are properly in gauge and all parts are properly lubricated. Of course wider radius curves would minimize it but we all have space limitations. Being an S gauge rather than O gauge operator I have no experience with what is normal with these engines.

Tom

[bfskinner]

When you consider that everything will run on a straight track; and that some locomotives, particularly those with a long driver wheelbase, will not make it around tight-radius track at all, it stands to reason that there must be increasing drag-and-skid around curves as the curves get tighter.

These forces on the locomotive, and the stringline effect on the train as a whole, not to mention Newton's Laws of Motion, combine to make going around curves inherently more difficult than moving on the straights.

If you had straight track as long* as the combination of straight and curved sections that you presently have on your layout, you'd be amazed at how well your train would go down that track at a nearly constant speed with only a single connection between transformer and track.

The losses in the track itself are minimal. What there is occurs principally at the joints between track sections. Bob "lionelsoni" Nelson has written extensively on this subject on this forum.

Simply put, it takes more "juice" to get around curves that it does to go straight.

* Or indeed much, much longer

. 

 

 

[servoguy]

 The problem engines have going around curved tracks is because the inner and outer rails are different lengths, and the drivers on each side are attached to a rigid axle.  Therefore, the drivers have to slip to go around the curve.  A real railroad avoids this problem by having a taper on the wheels of all the engines and cars which steers the wheels around the curves.

When a real engine encounters a curve, the outer and outer wheel ride to the outside of the curve.  This causes the outer wheel to contact the rail nearer the flange and the inner wheel to contact the rail further away from the flange.  Because the wheels are tapered, the outer wheel becomes larger and the inner wheel becomes smaller.  This steers the engine (and all the cars) around the curve.  With Lionel engines, there isn't any taper on the prewar and post war engines.  I just checked a new diesel engine, and it doesn't have any taper either.  The new cars do have tapered wheels, and should go around curves much better than the older cars.  The post war cars with the wheels turning on the axles should not have any problem going around curves.

I have often thought about making a set of wheels for a PW diesel to see if it would improve its performance through the curves, but that sounds too much like work.

Bruce Baker

[lionelsoni]

Gardner-Bender's Ox-Gard is meant for aluminum-to-aluminum and aluminum-to-copper connections.  In addition to blocking oxygen from the aluminum to prevent its oxidation, it also contains zinc powder, which is meant to cut through whatever oxide may already have formed on the aluminum.  It is reasonable to suppose that it would do the same for other oxidized surfaces, such as the tin-plated steel used for toy-train track.

It is not unique, however.  The competing grease, Noalox, from Ideal uses a similar zinc-powder formulation.  You may be able to find it if you can't get Ox-Gard.