Yep i just dug out the SD-40/2, it was a long time ago that i first tried it on DCC track and can say for sure that it should stay on DC.
It was the motor humming, quite badly too when running.
It does sound like a diesel idling though when stopped 

Cheers i suspect this is what it is and i did not get a chance to try it last night.
I will repost when i have tried it but from memory its quite a significant humming that sounds just like a diesl loco.
Standby.

edit: i have run hornby dc on this track and they work but obviously different brands means different results.

When i placed the loco from the Desert King set on a track powered by a Hornby digital  controller it made a continuous noise like an idling diesel.
Now there is no mention of DCC or SOUND anywhere on the box and i was quite surprised.
I cant actually get the train to move but this may just be an address issue, not sure.
I didn't leave the train on the track very long as i didn't want to damage anything and have since used it on the basic oval track from the Bachmann set successfully so i know i haven't done any damage to it.
Any help or info of any sort would be much appreciated.

Cheers Roddo

Hope you see this Buzz and Co.
The sets are still available in Aust and i have seen the ore cars packaged seperatly, but to get a loco you have to buy the set with the track and controller.

Anyway what i want to know is even though there is no mention of DCC or sound anywhere on the box, on the train, or on any written info, when i put my train on my digital hornby track it made a noise just like a train, but would not move.
The movement may be due to an address issue, not sure,
Does anyone have any idea whats going on?
Or was the train noise just a fluke and it was actually going into melt down mode?