Originally Posted by: RayF 
Hi John,
The stalling that I often get on the layout has nothing to do with turnouts, or even the centre studs. It is usually down to poor ground return through the running rails. Cleaning the rails usually eliminates the problems, although sometimes it is a problem with a particular loco having dirty axles, producing the same effect.
The worst affected parts of the layout are in sidings, which sometimes don't see as much use as the main lines.
Ray,
I can assure you it has something to do in my case odd enough my tracks are not dirty although the layout is not in an dust free environment and furthermore, my locos receive very little oil because of my locos having ballbearings in the motor and this partly eliminates oil finishing up on wheels or tracks.
I still find locos, when converting them for clients, there is a lot of oil underneath the slider.
Another reason is also by applying more oil than needed most of the time, the rubbertyres will expand anda 100% grip has gone.
Some older locos of mine, e.g. TM 800, Rm 800 and others I have had problems with dirty axles and cleaned them and it solved the problem.
Other issues such as oxidized copper part of the slider (stock items lying for years in boxes) has also prevented the loco receiving proper contact and even the slider itself received a film of somesort of oxididation and it needed a swipe with very fine sandpaper.
I'm somewhat surprised, anyone has problems with their locos, as I mentioned my layout is over 20 years old and had exposure to acidity and my locos are also exposed to humidity and I must say have survived over the many years.
Another reason could also be, having converted them over the years, they had a makeover and while converting them a maintenance check was done.
So in hindsight, looking at all the problems, it isn't just the centre stud.
regards.,
John