Diesel Assistance?

I'm new to the forum, so apologies if this has been dealt with already.

How can you tell if a WCRC train is being pushed by the diesel at the rear? I recently travelled behind 46233 (my first time behind a duchess) and was amazed at how quickly and smoothly she left York station. So much so that I suspected the diesel was helping. I spoke to the driver of the duchess at the water stop and he said there was no pushing. One of the volunteers on the train told me that the diesel is kept ticking over to carry its own weight, but does no more unless the steam loco is in trouble.
If this is correct, I'm very impressed both by 46233 and the skill of the driver.

Is there any way of telling whether the diesel is pushing if you are inside one of the coaches?

 

mmmmm I will sit back and wait for the debate to go nuclear on this one!!!!!

 

I don't know if it was the same trip but I photographed the Duchess romping away from March last week and there was certainly no assistance from the diesel. The Duchess is a very impressive machine, probably only matched by aMerchant Navy