I am relatively new in this hobby, two-three years of experience. I have built a layout in n-scale and I am operating with many different locomotives European and US (Trix, Fleishmann, Atlas, Bachmann, etc). However I continually face a lot of operational problems. The locos often stop working or they stuck unexpectedly in the middle of the track.
When I clean up the rails, using alcohol, the thing is getting better but does not disappear entirely. I would appreciate any tip or advise from people that have more experience than myself. Are these troubles n-scale related? Should I move upwards to H0, even if I have to compromise the space?
What Ken said. The problem is most likely the engines wheels and/or the track. Keep a log of what engines have problems where. You will see a pattern and can better determine exactly what the problem is.
Once you know the problem you will be able to isolate the cause. Please do not waste your money by switching to a larger scale when you just may make the same mistakes and have the same problems.