I'm used to racket that old worn locos can make, things like 3011/3014 etc can be quite noisy but a newly acquired and quite worn 3015 runs smoothly but makes a sort of 'gravel in a bucket' kind of noise which I assume is the gear chain chattering.

My only other croc is a 3352 which by comparison is almost silent but then it is a different beast from a different age...newest thing on my layout.

Is this fairly normal or is there something I should be looking at?

Nice video - thanks for posting the link.

Those older locos did not need recorded running sounds, they made their own, which I really like. My smooth silent new locos are sweet but I also love the intense mechanical nature of my earlier locos.

I think that is the sound which I would also expect for this model. The sound of honest machinery working and proudly doing its job.

I agree they didn't need running sound chips. Same for the early br 101's before Cardan drive. The gearing is quite loud.

Yes, I guess it does sound a bit like a sewing machine! My 3015 came to me in a mess, no pick ups, no pantographs, catenary power lever, tyres, bulbs or brushes.

I imagine someone stripped it to restore something else, well I have stripped an old SET800/3011 for some of the parts and got the pick ups from a couple of illuminated carriages but the brushes I have used are the small normal ones and not the larger type. These are on their way so will form a starting point for improving it.

This of course leaves me with a 3011 that needs rebuilding...and so it goes on...and on!