DCC non sound decoder install in Brass Steam

I think anyone is going to need more info? What model engine?

What drawbar with whisker wire are you describing? If it's just the spring wire that rubs on the pin, it's to keep continuity.

I haven't installed the 408 in at least a decade. I believe you're describing the pick-up wires that come from the rails?

I would look carefully at the wiring diagram. It was straight forward if I remember. Tony's Train exchange helped me years back get started. They suggested a inline fuse to protect things incase of shorts. You can look at their site for general install tips.

 If it won't fit in the boiler you have to install in the tender and have a tether.

Most older steam that I've worked on used to use one side of the engine for pick-ups and the opposite side of the tender. It depends on who made the engine!   If that's the case you either need to maintain that insulation between the units, or actually reverse the tender wheels so that they all pick-up on the same side. Then you install wipers on the insulated wheel backs to pick-up  from the other rail. 

Plastic bodied engines are more forgiving of wire rubs! Be careful. Insulate everything extra, and use wire ties to keep wires safe.

The red and black wires are the track pickups.    The red one is generally connected to the loco pickups and the black one to the tender pickups.     For the gray and orange to the motor, the orange most often goes to the engineer side for the default forward direction.     It makes no difference if the gray and orange are reversed because changing CV29 by one digit will change the normal forward direction. 

As Joe mentioned the drawbar is the tender pickup to the loco.    

Depending on the loco, you can sometimes fit the decoder in the boiler.   I have had no trouble doing that with most of bigger PRR models such mikados and decapods and k4s from USH.     I generally stuff it in above the weight.

A drawbar with a whisker implies newer perhaps sunset.

If you can fit decoder into the boiler, you can get by with only one wire from the tender for pickup only.    You could use the top of the whisker pin connection.    However if you want lights on the tender you need a wire for each light plus the ground.    Most of mine have back up lights so I use 3 wires - black for the track to the decoder and yellow for the backup light, and blue for the light common. 

I generally do not  use the pin, I use a 3 wire plug and socket.

Now if you have to put the decoder in the tender, you probably need 5 wires to the loco.     You need one for the red wire for the track pickups from the loco.    Then you need 2 for the gray and orange to the motor.    And 2 more for the headlight, white and blue.    You will need to get a 5 pin plug.     Micromark and Tony's train exchange sell them by the pin - you can get a strip of the 36 and cut your own.  

Use a light soldering iron when working with these plugs and sockets because it is easy to melt the plastic.     I seal the joints with shrink tubing too.

By the way, I have done a bunch of these and I really lke the decoder for motor control.    Also if  you burn out a light function, there 3 at least additional you can reprogram for front or rear lights.

Another question is are you going to use battery power or track power. My guess would be the red and black wires are for track power or to the battery 

Thanks Jim...good info. Not real sure there will be space in the boiler for the 408 decoder. But since that represents the least wiring I will check it out carefully. So the whisker (as I call it) on the drawbar aids in retaining the tender coupling pin but also carries the powered side of the tender forward. The drivers on the engineers side pickup power and are connected with a single lead to that insulated drawbar pin...is this a place for a potential short? Or am I overthinking this?

Thanks

Bob

Not exactly.  The draw bar pin is insulated from the engine frame.  Look closely where the bolt  that holds the draw bar to the engine...it passes thru a nylon or plastic bushing .  The draw carries LEFT rail current.  If your engine is set up for DC now, one wire connects to the left rail vis the draw bar tender and the other motor lead picks up right rail thru the right drivers and engine frame.