Dcc Decoders... Which size??

I'd email TOC and ask him what the max current draw is from his testing.

I do not believe that it is very high, especially being a geared loco. I have not converted mine yet, so I don't know. I try not to use 3 amp decoders unless they are really rugged because most G scale locos can pull more than this in a full stall. It's rare, but a couple more bucks for a beefy decoder is cheap insurance in my mind.

Let's look at the entire conversion, are you going to put sound in also? Do you have a short list of what you are thinking of in electronics?

Regards, Greg

I can say for sure that with a long train up a grade on dirty aluminium track, the two truck Shay with the plating worn off the wheels, will not trip an on board 3 amp Polyswitch.

I would be wary about "claimed" continual draw current capabilities of DCC decoders.

A Shay draws 2.3 amps at full slip and 7 amps at full stall. Most 3 amp decoders will handle this. If you don't want sound, use a DG583S, with sound, a QSI

- gws

Thanks for the input guys... The decoders that I was looking at are MRC and the 3 amp has 4 accessory channels but the 8amp doesn't have any so I'm kind of torn because I would like to put soud inand use that with the DCC connection. Any more thoughts??

Yes, MRC decoders can be temperamental, do your research to see if people had problems with the model you are looking at. Given the space available, I'd use the QSI since it's a single board and compact. Space is a bit tight.

If you go another way, and put 2 decoders in it, you will use up a lot more space.

There's also benefits on a single combination decoder, where the sounds will automatically track the actual load on the loco since the motor controller talks to the sound unit. It's not as important in a shay, since they really just sound like a sewing machine on steroids. If you were to go the 2 board route, either the digitrax as George suggested or almost any other 3-5 amp decoder. But now what sound unit will you use? It's an extra $220 for a Phoenix 2k2, or maybe $160 for a P5... you will be spending more money.

What do you want the "accessory channels" for?

Regards, Greg

I put a QSI in a Shay a few months ago...

http://www.girr.org/girr/tips/tips1/shay_tips.html

The Loksound XL works great in the Shay.

I get mine from Litchfield Station, good price, free shipping over $75 and they'll load the Shay sound file for you.