Model Railway Forum

Hi guys
I am looking for a bit of your vast knowledge
I recently picked up a reasonably good Class 52, having give it a good service and clean it was running very well, but suddenly started to slow down then speed up all the way round my layout.
The backs of the wheels are clean and also the wipers all cleaned with IPA. my track is also clean.
Looking at the wheels they are copper colour where they touch the track, i read somewhere that Heljan use brass wheelsets, is this a likely problem?
I see some people change the wheels for P4 sets, does anyone know what difference this change makes and would it be worth the change of wheel sets,
I am running my layout on DCC

I regret I can only offer vast opinions, little knowledge. In my own experience brass wheels, steel track,
not an issue. Peculiar that it ran well earlier, now not so well. One assumes these symptoms are limited
to this one locomotive, which is DCC? Deductively, one might suspect a bad decoder, (or
if not DCC then do the other locomotives run poorly? If that was the case, then one might suspect the
power pack).

A cheap solution is to give the track a good cleaning, again, and see if that rectifies the problem.
Perhaps you have a loose rail joiner that is providing poor electrical conduction? Is the wiring to the
rails and power pack in good order?

A lot of modelers prefer IPA as a cleaning solvent, but when I ran DCC some years ago I found that
the track accumulated enough grunge to produce exactly the kind of problems you are describing.
Worse yet, sometimes the decoder would not respond, and the train would prevail at top speed
into another train. It was soon learned that about 45 minutes between complete cleaning of wheels
and track was required using IPA under DCC.

There are other track cleaning solutions out there, from the expensive to the cheap. I prefer cheap, using
a method promoted by Lionel Strange, and that is Wahl's Hair Clipper Oil. Don't laugh until you've tried it.

One last cheap diagnostic tool is to take a miniature bulb, solder on a negative and positive set of wires,
and merely touch it to the rails around the layout. If the conductivity is poor, the light won't come on, or
will flicker, which tells you where to start looking. A voltometer, should you possess one, would do the same
thing, but the light bulb is pretty inexpensive.

Some Heljan models are known to have motors which take a lot of power, so the effect you are seeing may be the DCC chip overheating due to excess power draw.