Does anyone know if the K-Line B&A 4-6-4 is safe for 12v DC running? I didn’t take it today because I had other locos to try, but I’d like to take it to the next running day
Original Post
Replies sorted oldest to newest
I'm not familiar with that loco as such, but essentially all 3RO locos expect and require AC at the track, even if it is then rectified to DC internally per the design of the boards and motor - typically a DC permag/can motor. Putting DC on the track can lunch your electronics.
I think that some - many? - modern 3RO locos accept DC or AC as input power - they sense what it is and route/handle it as appropriate, at the speed of light. I've bought so few new items in the last 10 years that I'm out of touch, really. But any K-Line loco is, by definition, old, relative to this issue.
That’s the problem as I see it. The Berkshire is a “train set” loco and doesn’t have the fancy electronics, the Scout was built before it was even a word.
The 4-6-4 seems to me, to fall into that category of “too limited to risk it”. I don’t know, and I don’t want to damage it for that sort of reason.
I'll make this general observation: all "AC" motored Lionel engines will run quite nicely on DC. This because the familiar Lionel motors are NOT AC motors at all but rather series wound universal motors. At one time I operated a Lionel GP7 using a DC momentum throttle by substituting a bridge rectifier for the standard E-Unit. A bridge rectifier can be wired in such a way as to reverse the polarity of the armature (with respect to the field) when the DC track polarity is reversed. It works quite nicely.
Lew, they "run nicely" if you gut the reverse board or other electronics, I suspect that's the the question at hand!
Heh, John, I was referring to standard open-frame motors. 
Sure, with can-motored three-rail engines of course one needs to remove the electronic reversing unit and then it's a straight DC engine with no reversing dodge needed.
I just acquired an Atlas O three-rail SW9. Of course it has a can motor and a Dallee electronic reversing unit. This engine runs so smooth and slow I'm more than a little tempted to dump the whole AC bit. I'd just rip out the Dallee unit and wire the motor to the pickup rollers and frame. LED headlights and a simple diode array to switch headlights per direction of travel and I'd be done. I'd build what used to be called a DC "transistor" 
throttle. I might use some 60Hz pulse-width modulated voltage at the low end to encourage starts and slow-speed performance but the engine is so smooth I might just use straight DC.
