Well, I got a bad battery in my SD80MAC and to get to the battery I have to take the entire engine apart to replace it which really ruins your day so I decided to take some pictures of what makes these big engines run!
Ok, lets start out with the overall engine, not much to say here but geez there are too many wires...

Now lets focus on some actual parts, so our first stop is the brains of the engine, which is where the sound boards are located and the massive bundle of wires that control everything from motor speed to the smoke unit and when and how long the ditch lights will flash when you blow the horn.


Moving forward from there, you see the smoke unit, The piece that looks like a funnel is where the fluid that you put in through the stack funnels into to be heated and eventually blown right back out as a smoke ( sometimes very smelly :smile: )

Now to the motor, on each side of the engine you will see the motor with these odd white and black stripes on it and a little sensor, the sensor actually senses how many black stripes goes by per interval and tells the sound board if it needs to adjust the speed of the motor to maintain the desired speed of the engine the remote is set at!

This engine in my fleet is one of the oldest engines with the newer sound system ( Proto-Sound 2) and it has 10676.2 miles under its belt according to my remote and my latest loop is apx .7 to .8 Miles so this engine really has done some running and continues to be an engine that I can depend on no matter what, it has only been in for minor service like new traction tires and a new ditch light.
Ok now for the disclaimer: DON'T EVER take an O Scale engine apart under Warranty because chances are you void the warranty and if you do not have knowledge about what does what since the shells are very hard to get back on without breaking stuff and this messy engine is one of the more basic engines, so REALLY don't take apart something like a Lionel Vision Line Genset or ES44AC because you may have issues and break the engine!