K-Line cruise

Look into the motor amp draw of each engine, and compare them. Sounds like you are possibly pulling too many amps.

I am pulling 1.4 to 1.8 amps running pulling a 15 car consist (2 motors)

with the original board I would see up to 3.2 amps while running??

I agree with you, but I'm looking over something, but I don't know what yet.

Disconnect one motor and run on test rollers and see if there is a large difference in current between the 2.  If one is fairly higher than the other then there is your issue.

If the motor driver board dies I'd recommend a ERR Cruise Commander M in place of the K-Line one.

Jim

I agree, you may have one sick motor.

 Knowing the amps the Hudson used, or amps its board was rated at, could give a better indication of a possible current limiting issue, especially if the motors test out OK. 

 I doubt it really. But after all, though likely bigger, the Hudson had only one can motor right? With different gearing, it may have used a motor that used less amperage, and a circuit component to match. 

I'd be very concerned if the heatsink was getting up to 90C, you're knocking on the door to the maximum temperature rating of the parts.  Remember, the operating temperature of the drivers is die temperature, not package temperature.  If the heatsink is at 90C or more, the drivers are really cooking!

You must have excessive current draw.

yes, I went through the motors before posting anything here.

what I did find that is a substantial draw, is going through the motor direction wiring board that also contains the A/C power that powers the mars light board. (two resisters across the A/C power),I disconnected it for testing purposes.  (it took the resistance down to .7 at low speed operation and up to 1.5 at high speed.)the temp stayed down real well, I ran it for at least 3 hours at a scale 35 mph, it gradually got warm, unless I lowered the speed and it would cool back off again.

  As you said it has too much draw for that motor driver. 

it was a fun experiment .

I placed my order for two ERR 8amp drivers, I will un-tether the loco's and lash them up independent of each other.

SO the issue is not the motor, it is the accessory MARS board?  Maybe that is wired in wrong?  Or I am not following this, but it you unconnected the MARS lights and the engine is only drawing 2amps now, why add the ERR??

That seems normal.  Figure out what is wrong with mars unit or power it from track.  G

Well, as I described, after long running of 3 hours, it gradually made more heat than I liked. Just made more heat than I want.

Can you get a larger heat sink on it? (I think you said it has one)

 What kind of temp reading did you get after a few hours? The same?

And it doesn't need lube or have a "new to each other gear set" right. 

Well it was worth a shot to try, thanks for posting this. 

The motor driver board for a single motor Hudson being used for a 4 or 6 motor (if there is a powered B unit) E8 set. Does that seem right?

Certainly not 4 motors, but the cruise board rating is the same, I think about 8 amps.  The Allegheny is a 2 motor unit as example, a diesel would also be 2.

Driving an AA or AB powered with 4 motors total probably is a no no.  K-Line used a slave motor drive in some of the AA cruise diesels I have seen.  G