Brass or N/S wheels

The oxide on brass is non-conductive, while that on n/s is conductive. Both types look better when blackened. And both pick up less gunk than plastic wheels. I prefer n/s wheels.

I had this dilemma myself, but upon reading articles on gearsets, where it is not advisable not to have the same materials meshing with each other, because you get greater friction, then I did some tests to find out which type of wheel had the least rolling resistance. I realise the tests were not very scientific but firstly they put another nail in the coffin for plastic wheels as when a wagon was released on an incline with plastic and then N/S wheels, the N/S wheeled wagon rolled on average at least 25% more, the track being used was Peco N/S. At the time I did not have any vehicles with brass wheels so could not do any comparative tests to see if they provide any advantage, but subsequently I came to possess a coach which had brass wheels. I repeated the rolling resistance tests with a similar coach fitted with N/S wheels and the brass wheeled coach did fare a bit better but was not conclusive enough to make me standardise on any future rewheeling to brass wheelsets. Going back to gearsets articles, then if you fit N/S wheels on a loco and have N/S track then there should be increased friction between the two which should lead to less wheelslip but unfortunately you will use more power to move the train.

Ian Robinson

I don't think the wheels were the deciding variable in your rolling tests. The bearings would be what matters.

Why would you use more power? Less wheelslip would mean less wasted energy --> less power.

HTH

I was under the impression that if the wheels and the track were of the same material, that this helped reduce build-up of dirt, meaning less cleaning. I stand to be corrected however.

The bearings were not altered but if I had put in "Top Hats" then I would expect even better results.

Regarding the power used I did not think out the statement correctly as I was thinking about the friction between the N/S wheels on the stock causing more drag because of the friction but of course I had forgotten about the decrease in rolling resistance due to the metal wheels. Oops.

Ian Robinson

Um, I wasn't clear: I intended "bearings" to include the journals, i.e., the axle material. Oops. ;-)

Not to mention the axle pin point angles, (I've seem some models where the fixed conical cup has the same angle as the axle (or worse, cup deeper than axle!), so the bearing grinds round rather than ride on the pinpoint ).

- Nigel

I don't know about a brass to N/S interface, but electrical contact through dissimilar material can lead to bad conductivity over time. Gold plated v. tinned connector contacts are the usual area of concern, and should never be mixed.

MBQ