Transformer Woes

[RobertInOntario]

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

Fred,

Thanks again. I'm annoyed re that LHS. I recall that this transformer came in its own box, though, and it seemed to be packaged as if it were being sold on its own. At any rate, what you say makes sense & I'll look into getting a better transformer. I guess I'm gradually cooking this Athearn one by running old locos on it & using it for the turnout.

Cheers, Rob