1. I install details using photographs as a guide to match the prototype as much as possible. So, check out the web for pics of your loco.
2. Here is a link to several manuals, including installing sound from Soundtraxx using Tsunami's You would want a 2nd generation 645 prime mover. The speaker is key and I use a medium oval where it and the inside walls of the loco shell are filed down to fit. I make an enclosure by adding walls for the remaining sides.
http://www.soundtraxx.com/manuals.php
I normally use the AT format board since it's cheaper and small with a capacitor that can be upgraded.
Richard
Just bought a new Athearn RTR SD40T-2 as the local Hobby store was un packing it. Installed a Digitrax Dh 163 decoder in it it rung great and some what quite for a RTR but I have tow questions.1. Does any know where all the small parts that are in the plastic bags go the paper work really doesn't show all 2. What is the best and easiest way to install sound?thanks