Bachmann class 121 NSE 35-527

[Brian]

Its DCC Ready - PluX22 is the decoder fitting type. (Should you ever want it to become DCC operated). Example of loco... Link to click Inside it will have a PluX22 DC operation plug fitted to allow DC only operation. Example of a PluX22 decoder.. Decoder info link

You haven't mentioned what DC controller is being used? If its a basic Hornby train set one then seriously consider getting rid of the controller in favour of a Gaugemaster or Morley one.
You can try the loco with a fresh 9volt PP3 battery, either across the wheels of the loco or the battery connected across the rails with the DC controller removed. Of course you wont have speed control and it will run as fast as the battery allows, assuming it moves? To try it in reverse turn the PP3 battery around by 180 degrees so as Positive feed rail becomes a Negative feed one.

If it doesn't run a with a new PP3 battery return it as defective.

[davidrivett]

I was originally using one of the many spare Hornby controllers I have due to ease, but have just tried the gaugemaster 2 track controller.

Unfortunately the same outcome, lights on but nothing happening on the motor.

Also tried another couple of locos and they ran straight away perfectly.

Return to sender it is....