Transformer Woes

[pgandw]

Thanks, Fred. This is really helpful. The LHS who sold me the Athearn one assured me it was one of their better, most reliable transformers! When I first bought it, it did provide a fine range of speed so that my locos could creep along nicely at very slow speeds (both old and new). However, I do seem to have to crank it up more now.

Based on the above, what would be a good transformer for me to use, since I run a mixture of old & new locos on my layouts? Shall I stick with Railpower or are there other/similar ones? The Railpower ones were affordable yet I'm not sure if they're readily available these days.

Also, maybe I should use the Railpower one for the turnout rather than the Athearn one?

Thanks again,
Rob

In general, MRC DC power packs are pretty good. You want a minimum output of 15VA or watts (both are the same for our purposes) to run a mixture of trains. You also need a transistor-type throttle, not a rheostat. Any MRC Tech II or higher with the required output will do very well. Same with the Rail Power 1370, which is listed as a current product on the MRC web site.

Your LHS gave you some serious misinformation. The Athearn power pack was from a train set breakup - I don't believe Athearn ever sold power packs independently. At 7VA, it was designed to power the train set it came with - and nothing more.

For powering switch machines (I'm assuming twin coil - 3 wires - and not Tortoise), the ideal is a Capacitive Discharge (CD) unit. Circuitron makes one, or you can easily build one for less than $10 from on-line circuits as your first electronics project. The CD unit provides a jolt of high energy, just like a camera flash unit. This allows the switch machine (and the switch machine control) to do its job quickly and efficiently without overheating. The CD unit can use a small power pack (12VA or so) to recharge from in about 1-2 seconds. If not using a CD unit for your switch machines, you need 17VA or better for a power source. Even then, your trains will slow momentarily while the switch machine is sucking all the power.

hope this helps
Fred W