Since this is my third C-19 install, and others are documented with details here in other posts, I'll just share the basics and some pictures.
For my steam locomotive installs, I generally remove all the factory boards from the tender and wire direct using factory wiring. For the C-19, I also remove the weights in the tender. They are no longer needed for good track contact since I will be battery powered. I've included a a wiring chart for the C-19's tender plug harness which was developed with lots of help from folks who have good resources at Bachmann and access to full schematics of the loco.
Note that for the lighting and optical chuff trigger functions to work under RailPro, +5V must be provided to the electronics in the boiler and the switches behind the smoke box door need to be set to DCC.
I used a 4 Ohm speaker that was installed by the previous owner of this loco. I added an enclosure made from a plastic jar and sealed it all up with high temp hot glue. The 4 Ohm speaker is extremely loud! In the video linked below, RailPro master volume is at 35% and the steam sound file is at 70%.
I still use old school 5A mini blade fuses and and make my own holder from spade disconnects, removing the supplied insulation and soldering, rather than crimping, and cover the entire connector with heat shrink tubing.
I am a little OCD when it comes to wire management. Here is the tender after all was wired up...
And here is the chart detailing where each wire from the tender plug harness is connected to RailPro...
https://lsc.cvsry.com/Post2020/C-19Tender_Plugs.pdf Video embedding seems to be broken, so follow this link for a short video of all three of my dead rail RailPro controlled C-19s running as a triple header...
https://vimeo.com/750553538
